Hi Matthew, it looks like a GPU issue. Have you tried the following options:
1. Save, close, close and restart SW and open the drawing again.
2. Open the drawing from another computer.
My coworker just opened the file, it's doing the same thing on his computer. This wasn't an issue before the switch to 2019. I think it's a bug, I'll submit it to my vendor and keep everyone updated.
Has your VAR given you a SPR number? I'm having the same problem and wanted to reference your SPR number when I report this to my VAR.