In an application that uses QtPy with PySide6 as the back-end / binding library, I occasionally got a segmentation fault. I was able to reproduce the error in a minimal example. I've already reported the issue on the Qt for Python bug tracker—it includes an attachment with the example code—but they closed it as being out of scope, so I figured I would at least let the QtPy maintainers know that this segmentation fault can happen.
Perhaps my usage of the qtpy.uic.loadUi function is incorrect and there is a way to use it with the baseinstance parameter without risking a segmentation fault?