These issues occur almost always when I come out of stand-by (computer is not put to sleep, but monitors are put into stand-by mode, and machine is usually locked as well). The cancel button aberration is new, never seen that before on QT5 builds, but the minimized download window happened on both builds, QT5 based and QT6 based.

Regarding video drivers, I keep my video card (eVGA RTX 3080 Ti) fully updated with drivers as they are released by nVidia. However, I do use a slimming app to remove stuff that does not need to be there. One other application, KeePassXC, also QT5 based, never has such an issue with any of its windows, neither the main nor any child processes.

Since simply exiting out of FDM and starting it again works, it's low priority, honestly. I don't know of any trace programs I could use to try to help trace is down, or at the very least, give you an idea of where to look in order to reproduce it on your end, though.

I downloaded and installed and my FDM is now at version 6.20.0.5451 (build date: October 21, 2023), where is the changelog/release notes? Thank you!

6.20.0.5510 is released.