When you run a Qt app on Windows with the d3d11rhi and you do a graphics driver update (through GeForce Experience in my case), Qt just stop responding, the rendering stop and the whole window becomes white. Sometimes it also crashes. There's this trace in the output:
Device loss detected in ResizeBuffers()
Graphics device lost, cleaning up scenegraph and releasing RHI
You can easily reproduce with qml.exe and GeForce Experience by reinstalling the latest driver, no need to wait for a new release.
See in attachment the callstack when there's a crash.
I would expect Qt to appropriately handle this and keep running after the driver update.