It is a GPU preview bug. Turn on View > Preview on CPU to check.
What version are you using?
I'm using 26.3.1;
It however does not seem to be that, it's not turned on.
If you go to CPU preview, does that issue go away?
It does -.-
Thanks to both!
Hi @Yvonne Winters,
We are sorry for the trouble. This seems like an issue which we have tried addressing in the last release, v26.3.1. However, if you are on v26.3.1 and still facing the issue, I would suggest you upvote this UserVoice (https://illustrator.uservoice.com/forums/601447-illustrator-desktop-bugs/suggestions/43532958) and add your comment.
Also, would you mind sharing the download link to this file (upload it on Creative cloud or any similar service) and confirming on which zoom level you saw these weird artefacts/ jagged lines?
Looking forward to your response.
Thanks & Regards,