Khris, aventurero sent me game, and from what I see, he just did not do it correctly GUI-wise
. Unfortunately, project he uses is a mess at this point, inventory is on one Gui, "equipped" part is on separate gui; and he's got some extra "inventory" guis created for unknown purposes; I suggested he plan how inventory should look first and redo everything from scratch.
EDIT: Owww, just noticed that - he mess up with inventory types, as you guessed
He uses 1 for armor and 2 for weapons.
After I fixed that it worked well.

EDIT: Owww, just noticed that - he mess up with inventory types, as you guessed

He uses 1 for armor and 2 for weapons.
After I fixed that it worked well.