Hi Danw1nter,
Thanks for the post in Apple Support Communities. I understand you're seeing some unexpected vertical lines in Safari.
Does this happen when you open Safari initially as well, or if you open a new tab? Or is it only happening when you click a link in Safari?
Do you see similar behavior with any other apps or functions?
Which macOS version are you using under Apple menu () > About This Mac?
Does it help if you click Apple menu () > Restart and try again?
If not, I recommend booting your Mac into safe mode to test. This runs a quick diagnostic/repair and then prevents certain items from loading on startup: Use safe mode to isolate issues with your Mac. Once you reach your desktop in safe mode, test to see if you can replicate the issue. Then click Apple menu () > Restart to get back to normal. If you find Safari works as expected in safe mode, try the recommendations under the "If an issue doesn't happen in safe mode" section of the link above.
I hope this helps get you started.
Cheers.