"C:\Users \UserName \Documents \SH4" is oftentimes the "key". Be sure that after activating any new mod, that you
delete the contents of that SH4 save folder. If you use MultiSH4, delete the one you made there. If you have Windows managing the Documents folder on another drive, delete it from there. Just be sure and delete the old Save folder, else you have a mix of everything that came before, and it is usually not FotRSU that you see...
The 2nd most important thing, and again, with just about any mod (some more than others), is to correctly activate LAA or some other memory utility on the sh4.exe file.
Correctly.
There are issues in the mod, and s7rikeback found a few more today, but even if we do our absolute best, the mod is still the product of humans, as is the game, so "subject to issues", to say the least. But don't sabotage yourself further by not activating the mod correctly.