The main place where it will be observable is scary is in the SPI installer images.

The cause is known: it's https://github.com/Tow-Boot/Tow-Boot/blob/30d52a6747f389043853cb59cdae2f5ed01f8af8/support/builders/tow-boot/patches/0001-HACK-video-sync-dirty.patch.

The board is most likely fine, wait long enough, SPI erase and flash can be a slow operation at times. Waiting up to 5 minutes should be sufficient. Though those operations shouldn't last 5 minutes.

Forcing a sync on scroll may help with this issue.