PPSSPP saves imported to PSP

[Chk991]

I imported some of my saves from the PPSSPP folder to an actual PSP and while it works for most games, it doesn't seem to work for Idolm@ster SP.
For some reason it tells me my save is corrupted. I tried using MagiceSave to try and fix it but no dice. The save appears to be encrypted but that's not really a problem since PPSSPP saves encrypted files too.

The save works perfectly fine on PPSSPP by the way. My PSP has the latest 6.60 Pro-C2 CFW and aside from loading my game it works perfect. I suspect the issue might be related to the fact three games use the same savefile but I don't know for sure.