There's also really dirty screen fade outs in cps1 hardware where squares like this show and don't show incorrectly. It did not perform its intended duties perfectly but as for some certain glitches like this SF2 occurrence I don't have hard evidence one way or another and I doubt anyone else does either. But if I had to guess I'd say it's a natural hardware/software glitch like the others. This type of thing isn't limited to cps1 either.