[deleted] The flashing is worse in person
It looks bad enough in the video.
Just one thing I forgot: you're on the current release, right? Should be 2023111500. If not, you can first update to the most recent release to see if it's still happening.
Since this is a very strange issue, I'd suggest you open an issue in the OS issue tracker here: https://github.com/GrapheneOS/os-issue-tracker/issues. You can include the video you posted here so they can see the amount of flashing you're experiencing.
They'll most likely ask for logs. You can follow these instructions on how to get very detailed logs: https://developer.android.com/studio/debug/bug-report#bugreportdevice. I'd suggest restarting the phone, trigger the flashing again, then have the phone generate logs. Hold on to the logs and if/when a developer in the issue tracker asks for them, you can send the logs to them directly.