I've been experiencing a really weird bug recently:
Often when I zoom too much on a QGraphicsItem (using scale on the view containing it) that has a QGraphicsDropShadowEffect on it, my app closes with a segmentation fault (core dumped) error.
What's weird is that:

I use Python (with the PySide binding)
If I remove the QGraphicsDropShadowEffect, the bug disappears

I also had to remove the QGraphicsDropShadowEffect on a relatively big item because it got the app so slow to the point it became irresponsive when I zoomed a bit too much.
Do anyone know how I could fix this ?
This may or may not help but when I encountered this the only thing that helped was reinstalling/updating pyside. I thought the fixed that bug a while back however.
Qt : Segfault when zooming on QGraphicsDropShadowEffect