Basically, I've been having this bug on AI Studio since this summer: often, when I edit long text boxes, the layout starts blinking 1-2 times per second, with the text moving left and right.
I'm not sure how to explain it (English isn't my first language), but it's like it was looping between two different ways of rendering the text, and the frame becomes too small for the content (a horizontal scroll bar blinks in and out of existence, too).
This happens on both my home (Win 10 museum piece) and office (Win 10 recently upgraded to 11) computers, so it can't be hardware-related.
I tried some quick Internet searches, but I didn't notice anything that sounded related.
On both computers, I'm using the Grammarly extension, but I keep having the issue even when I disabled (but not uninstalled) it.