While scrolling through my question bank a series of errors kept popping up, each of which I just dismissed. This is the latest, and since it said it must be fixed by a programmer, I thought I'd add it here.
Coding error detected, it must be fixed by a programmer: Invalid value in set_user_preference() call, value is is too long for the value column

I wasn't doing anything except scrolling, although just before that I was trying to remove and resize columns. Can't replicate it.