Hahahaha, I guessed it!
This has been in the game since the very first version, and I see it a lot, but back then I searched for a while and couldn't for the life of me find where to fix it. I know what it is, but why it's sometimes there still baffles me... (it's some kinda of garbled error message from the engine itself, but I have no idea how it's getting there or where it's coming from, because it obviously isn't even properly using the spritesheet--very confusing!)
Anyway, I was guessing who would report this first, and I was right
. I'm sure others must've seen this before... though perhaps many would think it's even intended? I mean, it looks out of place, but not exactly terrible (and is mostly covered up quickly by the full hacking windows).
I'll look into it again since it's been a couple years since last time, although it's really hard to find because it's so random, without an obvious cause. Actually, in the next run this happens to you, could you attach a run.log here? I'll check if it contains any error clues, although if I recall correctly this is some kind of unlogged error (hence the confusion...).