I am just replying to say I have the same issue, to keep the thread alive. I also added my upvote to the Feedback Hub under the original post, and the new grouped post Microsoft have made with a misleading / incorrect title. It seems rubbish though, they
won't do anything on those Feedback Hub threads. I'm trying to go through the go-to threads about this (here, Intel and Reddit), but the responses do not look too promising.
The description of my issue is the same / similar to the others. A multi-monitor Windows 10 setup. In my case a Lenovo laptop with Intel graphics, connected to a dock, 2 monitors connected to the dock.
Randomly the behaviour will start on ONE of the monitors, where the top of the window will become blank (white) or black and it is not possible to interact with the top of the window. I notice there are no screenshots in this thread so I'll just add one
here, so everyone involved knows they are on the same lines! Ignore the grey privacy squares below, you will see one window which has been manually sized, and one which has been snapped / maximised.

I will let you know what worked for me once I have resolved the issue.