Is this where we report bugs?
So I haven't yet looked into this very deeply, nor do I have an adequate screenshot of the text log at this time, but I'm experiencing an issue with exclusive items. At least one of them isn't working, but I imagine it may be true of all exclusive items with that same effect.
Essentially, I'm playing as an aron, and I have the iron torc in the bag, which is supposed to prevent critical hits. I don't think it is doing as such however. As a matter of fact, it seems to increase the damage of critical hits.
Quoting the text log from memory:
Admittedly, this is while using MelonDS. I'm working on setting up a different emulator. Will edit this if I find things are different with a different emulator.
edit: It seems that melonDS is the only emulator DS emulator out there that supports Linux. I don't have a windows computer, and I don't plan on buying a windows license, or risking Windows's destructive installation process just for this. I therefore cannot test this on a different emulator at this time.