Many times, developers intend their game to be ran at a certain frame rate, or program stuff using the frame rate in mind. There are quite a few games out on the market that have frame limits of 30/60 locked by the developers due to their game having strange bugs/issues arise when you go above that threshold. (Fallout 76 for example, your character actually moved FASTER the higher your frame rate, giving unfair advantage to people with better computers).
Even in this game, a reddit post showed that when you hit >100 fps, cloth and jiggle physics just seemingly stop functioning and break, meaning something in the game's code is tied to frame rate. It's an un-optimal practice when it comes to coding, but its a quick and easy one in most cases, hence why it still happens in games today. They most likely capped the frame limit at 90 to prevent any other weird things from happening.