Another example that makes no sense... When I have 'Edge' open, and I place my cursor in the Search box, the graphics that show up in the search window all have the X's. But the graphics in Edge that show up behind the search window, are just fine.
A week ago, I added more RAM -- I have 24 GB. I had 8 GB. But the PC had the problem long before that. I say that just to point out that I did switch the RAM slots for the DDR4 memory. I don't know how the RAM used for graphics is selected, but, very likely, a different RAM stick is being used for the video now than it was a week ago. And there was no changes in this odd effect.