I have an app that use [android-maps-utils][1] and [glide for marker icons][2].&lt;br&gt;
I got an error report using Firebase crash reporting which I can&#39;t track in source code because `gms.maps.model.Marker.setIcon` is private, so I&#39;m asking for some help with this problem.&lt;br&gt;
The follow part of the question is divided into:&lt;br&gt;

 - What the user was doing
 - What firebase crash reported to me
 - Some project configs
 - What I tried/found trying to understand/fix it

**What the user was doing**&lt;br&gt;
He was zooming in and out in a map (`Fragment` that uses `com.google.android.gms.maps.SupportMapFragment`)
&lt;br&gt;

**What firebase crash reported to me**&lt;br&gt;

&gt; Exception java.lang.IllegalArgumentException: Unmanaged descriptor&lt;br&gt;
com.google.maps.api.android.lib6.common.k.b (:com.google.android.gms.DynamiteModulesB:162)&lt;br&gt;
com.google.maps.api.android.lib6.impl.o.c (:com.google.android.gms.DynamiteModulesB:75)&lt;br&gt;
com.google.maps.api.android.lib6.impl.db.a (:com.google.android.gms.DynamiteModulesB:334)&lt;br&gt;
com.google.android.gms.maps.model.internal.q.onTransact (:com.google.android.gms.DynamiteModulesB:204)&lt;br&gt;
android.os.Binder.transact (Binder.java:387)&lt;br&gt;
com.google.android.gms.maps.model.internal.zzf$zza$zza.zzL ()
com.google.android.gms.maps.model.Marker.setIcon ()&lt;br&gt;
co.com.spyspot.ui.content.sucursal.SucursalRender$CustomSimpleTarget.onResourceReady (SucursalRender.java:156)&lt;br&gt;
co.com.spyspot.ui.content.sucursal.SucursalRender$CustomSimpleTarget.onResourceReady (SucursalRender.java:130)&lt;br&gt;
com.bumptech.glide.request.GenericRequest.onResourceReady (GenericRequest.java:525)&lt;br&gt;
com.bumptech.glide.request.GenericRequest.onResourceReady (GenericRequest.java:507)&lt;br&gt;
com.bumptech.glide.load.engine.EngineJob.handleResultOnMainThread (EngineJob.java:158)&lt;br&gt;
com.bumptech.glide.load.engine.EngineJob.access$100 (EngineJob.java:22)&lt;br&gt;
com.bumptech.glide.load.engine.EngineJob$MainThreadCallback.handleMessage (EngineJob.java:202)&lt;br&gt;
android.os.Handler.dispatchMessage (Handler.java:98)&lt;br&gt;
android.os.Looper.loop (Looper.java:148)&lt;br&gt;
android.app.ActivityThread.main (ActivityThread.java:5443)&lt;br&gt;
java.lang.reflect.Method.invoke (Method.java)&lt;br&gt;
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run (ZygoteInit.java:728)&lt;br&gt;
com.android.internal.os.ZygoteInit.main (ZygoteInit.java:618)

And:&lt;br&gt;

[![enter image description here][3]][3]
&lt;br&gt;

**Some project configs**&lt;br&gt;

 - I&#39;m using a Custom Render (`SucursalRender extends DefaultClusterRenderer&lt;Sucursal&gt;`)
 - I&#39;m downloading the Marker icon with Glide like I said before: `Glide.with(context).load(id).fitCenter().placeholder(R.drawable.ic_no_image).into(simpleTarget);`

The `simpleTarget` is where I handle the images downloaded/cached for Glide. I&#39;m posting all code about `simpleTarget` because the crash is starting there:&lt;br&gt;

    private class CustomSimpleTarget extends SimpleTarget&lt;GlideDrawable&gt; {
        Sucursal sucursal;
        Marker markerToChange = null;

        @Override
        public void onResourceReady(GlideDrawable resource, GlideAnimation&lt;? super GlideDrawable&gt; glideAnimation) {
            mImageView.setImageDrawable(resource);
            //currentSelectedItem is the current element selected in the map (Sucursal type)
            //mIconGenerator is a: CustomIconGenerator extends IconGenerator
            if (currentSelectedItem != null &amp;&amp; sucursal.idalmacen.contentEquals(currentSelectedItem.idalmacen))
                mIconGenerator.customIconBackground.useSelectionColor(true, ContextCompat.getColor(mContext, R.color.colorAccent));
            else
                mIconGenerator.customIconBackground.useSelectionColor(false, 0);

            Bitmap icon = mIconGenerator.makeIcon();

            if (markerToChange == null) {
                for (Marker marker : mClusterManager.getMarkerCollection().getMarkers()) {
                    if (marker.getPosition().equals(sucursal.getPosition())) {
                        markerToChange = marker;
                    }
                }
            }

            // if found - change icon
            if (markerToChange != null) {
                //GlideShortcutDrawable is a WeakReference&lt;&gt;(drawable)
                sucursal.setGlideShortCutDrawable(resource);
                markerToChange.setIcon(BitmapDescriptorFactory.fromBitmap(icon));
            }
        }
    }

The **crash** is being thrown in last line of code: `markerToChange.setIcon(BitmapDescriptorFactory.fromBitmap(icon));`
&lt;br&gt;&lt;br&gt;

**What I tried/found trying to understand/fix it**

 - Tried to reproduce the error in 4 real devices without success.
 - Searched in web for similar errors or code about `gms.maps.model.Marker.setIcon` or `com.google.maps.api.android.lib6`
 - Tried to understand the obfuscated code given in Android Studio for `Marker.setIcon`&lt;br&gt;

I guess I can wrap the code in a `try-catch block` for that IllegalArgumentException: Unmanaged descriptor to avoid application get closed because the crash but it&#39;s just a work around it.

**update 2**&lt;br&gt;
The code of `DefaultClusterRenderer`:&lt;br&gt;

    public class SucursalRender extends DefaultClusterRenderer&lt;Sucursal&gt; {
        /**
         * Create a customized icon for markers with two background colors. Used with {@link com.google.maps.android.clustering.ClusterItem}.
         */
        private final CustomIconGenerator mIconGenerator;
        /**
         * Marker image.
         */
        private final ImageView mImageView;
        /**
         * Create a customized icon for {@link Cluster&lt;Sucursal&gt;} with a single background.
         */
        private final IconGenerator mClusterIconGenerator;
        /**
         * Cluster image.
         */
        private final ImageView mClusterImageView;
        private final Context mContext;
        /**
         * Keep a reference to the current item highlighted in UI (the one with different background).
         */
        public Sucursal currentSelectedItem;
        /**
         * The {@link ClusterManager&lt;Sucursal&gt;} instance.
         */
        private ClusterManager&lt;Sucursal&gt; mClusterManager;
    
        public SucursalRender(Context context, GoogleMap map, ClusterManager&lt;Sucursal&gt; clusterManager) {
            super(context, map, clusterManager);
    
            mContext = context;
            mClusterManager = clusterManager;
            mIconGenerator = new CustomIconGenerator(mContext.getApplicationContext());
            mClusterIconGenerator = new IconGenerator(mContext.getApplicationContext());
    
            int padding = (int) mContext.getResources().getDimension(R.dimen.custom_profile_padding);
            int dimension = (int) mContext.getResources().getDimension(R.dimen.custom_profile_image);
    
            //R.layout.map_cluster_layout is a simple XML with the visual elements to use in markers and cluster
            View view = ((AppCompatActivity)mContext).getLayoutInflater().inflate(R.layout.map_cluster_layout, null);
            mClusterIconGenerator.setContentView(view);
            mClusterImageView = (ImageView) view.findViewById(R.id.image);
            mClusterImageView.setPadding(padding, padding, padding, padding);
    
            mImageView = new ImageView(mContext.getApplicationContext());
            mImageView.setLayoutParams(new ViewGroup.LayoutParams(dimension, dimension));
            mImageView.setPadding(padding, padding, padding, padding);
            mIconGenerator.setContentView(mImageView);
    
            CustomIconBackground customIconBackground = new CustomIconBackground(false);
            mIconGenerator.setBackground(customIconBackground);
            mIconGenerator.customIconBackground = customIconBackground;
            mClusterIconGenerator.setBackground(new CustomIconBackground(true));
        }

        ...
        
        @Override
        protected void onBeforeClusterItemRendered(final Sucursal sucursal, MarkerOptions markerOptions) {
        
            mImageView.setImageDrawable(ContextCompat.getDrawable(mContext, R.drawable.ic_no_image));
            Bitmap icon = mIconGenerator.makeIcon();
            markerOptions.icon(BitmapDescriptorFactory.fromBitmap(icon));
        }

        @Override
        protected void onClusterItemRendered(Sucursal clusterItem, Marker marker) {
            CustomSimpleTarget simpleTarget = new CustomSimpleTarget();
            simpleTarget.sucursal = clusterItem;
            simpleTarget.markerToChange = marker;
            ImageLoaderManager.setImageFromId(simpleTarget, clusterItem.logo, mContext);
        }

        @Override
        protected void onBeforeClusterRendered(Cluster&lt;Sucursal&gt; cluster, MarkerOptions markerOptions) {
            mClusterImageView.setImageDrawable(ResourcesCompat.getDrawable(mContext.getResources(), R.drawable.ic_sucursales, null));
            Bitmap icon = mClusterIconGenerator.makeIcon(String.valueOf(cluster.getSize()));
            markerOptions.icon(BitmapDescriptorFactory.fromBitmap(icon));
        }

        @Override
        protected boolean shouldRenderAsCluster(Cluster cluster) {
            // Always render clusters.
            return cluster.getSize() &gt; 1;
        }
        
        /**
         * Just extends {@link IconGenerator} and give the ability to change background.
         * Used to know highlight the current selected item in UI.
         */
        private class CustomIconGenerator extends IconGenerator {
            private CustomIconBackground customIconBackground;
            private CustomIconGenerator(Context context) {
                super(context);
            }
        }
    
    
        /**
         * Create a custom icon to use with {@link Marker} or {@link Cluster&lt;Sucursal&gt;}
         */
        private class CustomIconBackground  extends Drawable {
    
            private final Drawable mShadow;
            private final Drawable mMask;
            private int mColor = Color.WHITE;
    
            private boolean useSelectionColor;
            private int mColorSelection;
    
            private CustomIconBackground(boolean isCluster) {
                useSelectionColor = false;
    
                if (isCluster) {
                    mMask = ContextCompat.getDrawable(mContext, R.drawable.map_pin_negro_cluster);
                    mShadow = ContextCompat.getDrawable(mContext, R.drawable.map_pin_transparente_cluster);
                }
                else {
                    mMask = ContextCompat.getDrawable(mContext, R.drawable.map_pin_negro);
                    mShadow = ContextCompat.getDrawable(mContext, R.drawable.map_pin_transparente);
                }
            }
    
            public void setColor(int color) {
                mColor = color;
            }
    
            private void useSelectionColor(boolean value, int color) {
                useSelectionColor = value;
                mColorSelection = color;
            }
            @Override
            public void draw(@NonNull Canvas canvas) {
                mMask.draw(canvas);
                canvas.drawColor(mColor, PorterDuff.Mode.SRC_IN);
                mShadow.draw(canvas);
    
                if (useSelectionColor) {
                    canvas.drawColor(mColorSelection, PorterDuff.Mode.SRC_IN);
                    useSelectionColor = false;
                }
            }
    
            @Override
            public void setAlpha(int alpha) {
                throw new UnsupportedOperationException();
            }

            @Override
            public void setColorFilter(ColorFilter cf) {
                throw new UnsupportedOperationException();
            }
    
            @Override
            public int getOpacity() {
                return PixelFormat.TRANSLUCENT;
            }
    
            @Override
            public void setBounds(int left, int top, int right, int bottom) {
                mMask.setBounds(left, top, right, bottom);
                mShadow.setBounds(left, top, right, bottom);
            }
    
            @Override
            public void setBounds(@NonNull Rect bounds) {
                mMask.setBounds(bounds);
                mShadow.setBounds(bounds);
            }
    
            @Override
            public boolean getPadding(@NonNull Rect padding) {
                return mMask.getPadding(padding);
            }
        }

The `ImageLoaderManager` is just a Facade for Glide.

    public static void setImageFromId(SimpleTarget&lt;GlideDrawable&gt; simpleTarget, String id, Context context) {

        if (context instanceof AppCompatActivity) {
            AppCompatActivity activity = (AppCompatActivity)context;
            if (activity.isDestroyed())
                return;
        }
        Glide.with(context)
                .load(id)
                .fitCenter()
                .placeholder(R.drawable.ic_no_image)
                .into(simpleTarget);
    }
        

  [1]: https://github.com/googlemaps/android-maps-utils
  [2]: https://github.com/bumptech/glide
  [3]: https://i.stack.imgur.com/yW2y6.png

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IllegalArgumentException: Unmanaged descriptor using gms.maps.model.Marker.setIcon