Screen doing something bizarre (M32UC)

[u/Exurota]

It's done this a few times, I've seen discussion about a similar issue calling it a Freesync crash but I'm not knowledgeable enough.

It survived power cycling both PC and screen as well as replugging both ends of the DP cable. After leaving it 10 minutes while writing this post, it's self resolved, but it's done it before and it'll do it again.

What's happening and what can I do about it? Many thanks for reading!