Editor crashes semi-randomly

Editor application crashes randomly, often when left to background but occasionally when used actively. This is hard to catch as crashes do not seem to happen when debugger is attached, but debugger stops periodically when swapbuffers is done, with following output:

HEAP[Qt3DStudio.exe]:

HEAP: Free Heap block 20211058 modified at 2021106C after it was freed

HEAP[Qt3DStudio.exe]:

HEAP: Free Heap block 20211058 modified at 2021106C after it was freed

HEAP[Qt3DStudio.exe]:

HEAP: Free Heap block 20211058 modified at 2021106C after it was freed

(...)

edit: Occasionally an exception after QmlStreamer render call can be caught in debugger, possibly related to memory issues above.

Occurs with head at 43d1f99ea4ea8aee825fabcdd7ec9fdad9a6539f, with SampleProject being open.