A lot of comments here kind of brush off the fact that this has been going on for _years_! I would expect quadratic behaviour to slip here and there in non real time code places. We make mistakes after all.
I've had to revisit production code from time to time to discover my or my colleague assumptions about library functions were not actually true.
But for someone in the possession of the source code this looks like _minutes_ worth of profiling time! With a stellar technical accomplishment that GTA5 truly is, you would expect tons of really talented devs that could have traced this one down on their lunch break.
The fact that they didn't speaks volumes about organisational structure within R*. I think some higher up managers _really_ need some stern talking to!