Reporting the same issue here with the very same experiences as others on this thread.
Has been occurring in our environment for at least 6 months.
Multiple users in an enterprise environment.
All use Office 365. All use multiple monitors.
All are on different hardware. Laptops, desktops, varying graphics hardware. Even tried replacing GPU in one desktop to no avail.
All have latest graphics drivers, BIOS, and Windows updates. Even occurs on brand new machines with the freshest Windows 10 installed from the media creation tool.
No real fix. Win+Ctrl+Shift+B seems to work best. Some success with the Intel graphics settings.
This is so obviously a bug in Microsoft's court and would appreciate some real investigation from Microsoft and at least a response as this has been seriously affecting many users for quite some time.