Recently when resuming Windows 10 Pro ARM, mouse clicks work but the hover events do not. To get hover events working again I have to click out of Windows 10 Parallels to the Finder, then click back into the Parallels/Windows 10. Seems this just started happening possibly with a Windows update? Hover events are when you mouse over things like the Start Menu, Window Menus, Window Close, etc. Anyone else?
I'm also having this issue. I upgraded to Big Sur and Parallels 17 around the same time this issue started so either or neither could be the cause - I can't say for certain. mbook's workaround of clicking to the Finder and then going back to Parallels/Windows 10 also works for me, but it would be great to actually fix this issue as it's quite annoying.
OP has elaborated on the matter quite well. Unfortunately, I'm also having the issue. Fortunately, the workaround still works, though. Kudos to you!