TL;DR Turn off “Phone Audio” in the Bluetooth headset.
I have had a very strange problem with my LineageOS phone over the last week or two. Every screen intermittently started refreshing every second or so. Side menus disappeared, videos when back to the start, keyboard prediction went nuts. I hadn’t changed my hardware setup at all and could not get to the root cause. I did a clean install again but the problem remained which lead me to think that it may be a hardware problem with the phone.
Just my luck that the problem only seemed to happen when I went on breaks, or during my commute. During my work day the phone preformed fine.
I use a cheap Bluetooth headset to listen to podcasts but I didn’t think that was the issue as it’s been working fine for a year or more. However I happened to be looking at the screen while I turned them on, and wouldn’t you know the problem started. I turned off Bluetooth and the problem went away. Finally turning off “Phone Audio” fixed the issue entirely.
This issue is limited to this adapter only and other headsets don’t have the problem.