So, I’m using the modular save in my hack which allows up to 62 playable units. However, once reaching this limit, this causes a few bugs in the game - namely, ones I’ve experienced on my own being not being able to start the chapter from the view map screen.
However, other people have reported not being able to view map at all, with the game crashing and their save data being deleted, or simply not being able to reorder units on the screen.
Vanilla supports up to 50 units. Saving more in ram with ems is one thing, but it doesn’t touch prep, which only supports 50. If it doesn’t break with more than 50 active units most of the time, then that’s just luck. Maybe the undefined behaviour gets consistently worse somewhere specific between 51 and 62 - I don’t know. But it is a buffer overflow past 50, and unintended behaviour may occur.
Solution is to make it so you can only have 50 simultaneously.
I made an attempt at increasing the party size in my coding thread, which does increase it past 50, but it’s not a perfect solution either.