Thank you Tonio for the reply. Yes, I tested it again and seems only sync issue between views by the SNAP. the actual coordinate extent is correct.
However, the coordinates still seems problematic : with the input images as projected coordinates, for example Albers; after binning , coordinates will be Lat/Lon (?); to keep consistency with other layers, I need to reproject back to Albers using gpt reproject. But received error msg:
....10%...Exception in thread "SunTileScheduler0Standard36" java.lang.NullPointerException
at com.sun.media.jai.util.SunCachedTile.<init>(SunCachedTile.java:80)
at com.sun.media.jai.util.SunTileCache.add(SunTileCache.java:257)
at javax.media.jai.OpImage.addTileToCache(OpImage.java:1087)
at javax.media.jai.OpImage.getTile(OpImage.java:1142)
at org.esa.snap.core.gpf.internal.OperatorExecutor$OperatorTileComputationListenerStack.tileComputed(OperatorExecutor.java:310)
at com.sun.media.jai.util.RequestJob.compute(SunTileScheduler.java:278)
at com.sun.media.jai.util.WorkerThread.run(SunTileScheduler.java:468)