If I launch the game through the Infinity Final Fantasy XIII-2 Trainer, then the game crashes every time I pick a level after loading my save. Does not happen if I just launch the game from Steam though.
Launch the game trough steam and attach Infinity afterwards (press play when you are loaded in)
That works as long as I’m in an area I’m exploring, but as soon as I use a gate or switch areas via the Historia Crux, the game crashes again. 
You have any cheats activated while switching areas or just Infinity attached to it?
If so try deactivating them before you switch areas
Disabling cloud saves fixed my issue 100% for some reason.
Hi I also have the same problem as soon as I use infinity as I run it after or before the game crash anyway, how do you keep playing without the cloud? because I tried but my backup was gone ( i am french )
Hello. the game still crashes when using this trainer