Desmume save files not loading (sometimes) (M&L:BIS specific) ??

[TheBeautifulAngel]

I've been having an issue where certain NDS games will not open their respective save files. I usually start a save on another machine and move it over to this rig later. I've had no problems doing this for official copies of Pokemon Black, Platinum and Emerald and ROMHacks, but when I try to open Mario&Luigi:Bowsers Inside Story it refuses to load my DSV or SAV files. I have configured them like every other save file which worked so I am very confused. I have tried:

Renaming saves to exactly match the ROM name
Changing DSR and SAV files to other extensions like SRM and RTC
Toggling off all the "Use this save for this directory" saving settings in the app
Moved the save files into the cores directory, general messing around with save paths

I've tried using different DS cores besides desmume and all my other ROMS on this rig work except this one. It is my favourite game OAT and Id love to play it again.
I am absolutely positive the save does actually work too because I just tried running it on my other machine with no worries. I also know this game is notoriously weird to emulate, given the sideways battles and such. Perhaps just some weird mechanic where the game doesnt work with exportable SAV files? Maybe someone here knows something that is staring me in the face? Pls someone help me thanks :)