Big Sur: assertion in NSView _transformFromView when going full screen

One of my apps, which works fine on Catalina. consistently crashes when I go full screen in Big Sur beta 1, with the following assertion. None of the code omg the stack involved is my own.

this happened with my previously built (against Catalina) binary, as well as when I rebuild it against the macOS 11 SDK.

Is anyone seeing something similar, or has any idea what could be wrong?

Assertion failed: (commonAncestor != nil), function -[NSView _transformFromView:], file /AppleInternal/BuildRoot/Library/Caches/com.apple.xbs/Sources/AppKit/AppKit-1997/AppKit.subproj/NSView.m, line 6486.
3:35

Code Block
Main Thread (1) Queue : com.apple.main-thread (serial)
#0 0x00007fff694ef842 in pthread_kill ()
#1 0x00007fff695b5671 in pthread_kill ()
#2 0x00007fff694627c0 in abort ()
#3 0x00007fff69461a76 in assert_rtn ()
#4 0x00007fff26903868 in -[NSView _transformFromView:] ()
#5 0x00007fff26c92f8b in 27-[_NSPortalView2 drawRect:]_block_invoke_2 ()
#6 0x00007fff26606f09 in +[NSAppearance _performWithCurrentAppearance:usingBlock:] ()
#7 0x00007fff26c92f20 in 27-[_NSPortalView2 drawRect:]_block_invoke ()
#8 0x00007fff26645749 in -[NSFocusStack performWithFocusView:inWindow:usingBlock:] ()
#9 0x00007fff26c92e7b in -[_NSPortalView2 drawRect:] ()
#10 0x00007fff2678a38a in _NSViewDrawRect ()
#11 0x00007fff26e9d13e in -[NSView _recursive:displayRectIgnoringOpacity:inContext:stopAtLayerBackedViews:] ()
#12 0x00007fff267899b0 in -[NSView(NSLayerKitGlue) _drawViewBackingLayer:inContext:drawingHandler:] ()
#13 0x00007fff33c47241 in CABackingStoreUpdate_ ()
#14 0x00007fff33caa719 in invocation function for block in CA::Layer::display_() ()
#15 0x00007fff33c4678d in -[CALayer _display] ()
#16 0x00007fff267891d4 in -[_NSBackingLayer display] ()
#17 0x00007fff266f4d4a in -[_NSViewBackingLayer display] ()
#18 0x00007fff33c457b2 in CA::Layer::display_if_needed(CA::Transaction*) ()
#19 0x00007fff33d77379 in CA::Context::commit_transaction(CA::Transaction*, double, double*) ()
#20 0x00007fff33c2349d in CA::Transaction::commit() ()
#21 0x00007fff2679e815 in 62+[CATransaction(NSCATransaction) NS_setFlushesWithDisplayLink]_block_invoke ()
#22 0x00007fff26ed2c25 in _NSRunLoopObserverCreateWithHandler_block_invoke ()
#23 0x00007fff296de055 in CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION ()
#24 0x00007fff296ddf70 in CFRunLoopDoObservers ()
#25 0x00007fff296dd5a6 in CFRunLoopRun ()
#26 0x00007fff296dcbea in CFRunLoopRunSpecific ()
#27 0x00007fff280c3dd0 in RunCurrentEventLoopInMode ()
#28 0x00007fff280c3bc9 in ReceiveNextEventCommon ()
#29 0x00007fff280c38ec in _BlockUntilNextEventMatchingListInModeWithFilter ()
#30 0x00007fff26619e2b in _DPSNextEvent ()
#31 0x00007fff26618659 in -[NSApplication(NSEvent) _nextEventMatchingEventMask:untilDate:inMode:dequeue:] ()
#32 0x00007fff2660ab4b in -[NSApplication run] ()
#33 0x00007fff265dea58 in NSApplicationMain ()
#34 0x000000010588c4b7 in +[Program Main::] ()
#35 0x00007fff69389c71 in start ()
#36 0x00007fff69389c71 in start ()

Sorry you're hitting this. Could you file a report using Feedback Assistant with the crash logs you're getting?
Will do, thanx!
Done: FB7814726

Hello, I have the same problem,my app works fine in 10.15 but crashes when I go full screen in Big Sur beta4, I want to ask if you have found a solution?
Big Sur: assertion in NSView _transformFromView when going full screen
 
 
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