tl:dr; the PS2 does floating point calculations slightly wrongly; most games that depended on the exact calculations have just received runtime patches and workarounds, but a couple of them are too difficult. Calculating the exact wonky values is slow, but fixes lots of games.

Not too surprising that a system that only requires calculations to be accurate enough for a relatively low-res 3d render would prioritise speed over accuracy. On the plus side, at least the developers have only used weird behaviour to try and squeeze the last bits of performance out of the system. An Amiga emulator that runs the cracked versions of games will run on your phone. One that's cycle-perfect enough to get through all the copy protection schemes needs a damned supercomputer.