In large scale online games you have issues ranging from obscure things causing memory leaks based on drivers, hardware combinations, etc. and all the way to basic things getting overlooked. One of my favorite examples being GTA5 online.

They forgot to update a function from early testing, and it was in the game for about a decade before someone else debugged the launch process. And then realized that it was going through the entire comparison file for each item it checked on the local list. So “changing a few lines” ended up reducing initial load times by up to 70% depending on the cpu and storage media.

EDIT: I’ve been drinking and probably misreemebred parts, so here is the post about how he found the issue

That’s nothing new.

Gamers who don’t know any programming, or maybe made a little utility for themselves. Looovee to bring out the old “just change one line of code”, “just add this model”, etc. to alter something in a game.

They literally do not understand how complex systems become, specially in online multiplayer games. Riot had issues with their spaghetti code, and people were crawling over eachother to explain how “easy” it would be to just change an ability. Without realizing that it could impact and potentially break half a dozen other abilities.