Ok, after some testing with different midis, I've found out this whole 0 reverb even when cc91 it's not at 0 only happens with some midis, specifically the unedited ripped midis from some gba games (not even in all gba rips, but in most of them) by GBAMusRiper
Those midis gotta have something weird in them, If I open them with Mixcraft and then save them as midi (without changing anything in the midi) they sound exactly the same but with reverb working
After disabling effects - applying - enabling effects - applying - reset midi player all these gba midis' reverb work until you close VMS
Also to reproduce this bug you need to close all blocking midi processes (the sames ones blocking installation of VMS) or else after you open VMS the reverb will still work on these midis, so basically:
- After disabling/enabling effects the reverb effect works on these midis, so to reproduce the bug you gotta reset VMS
- Close processes using VMS and then VMS
- Close possible blocking midi processes (at least in my case the bug didn't start to happen after reseting VMS unless I closed famitracker which I remember it blocked the VMS installation)
- Open VMS manually or directly by opening a midi with this problem (make sure said midi doesn't have cc91 on all channels set to 0, some songs have it at 0 on all channels) and the reverb shouldn't happen anymore
I won't upload any midis for now because I don't know wherever it's allowed to or not to upload midis from comercial games here
If I can, tell me and I will upload the whole midi collection and the soundfont, If I can't you can convert it yourself with GBAMusRiper (the only GBA game in my collection where this bug doesn't happen it's with Street Fight 2 revival)
This bug it's very specific, no wonder it seemed so random