Alright, got that sorted out for you in v1.29.
Basically, the problem was a typo. In an if check I'd checked if the items etypeId was == 2, instead of >= 2. Meaning it could only ever allow armor that was etypeId 2, or shields. That's concerning, because that function has been the same since the beginning, I'm pretty sure, so this bug has always existed.
Thanks for the catch.
~Ramza