I have default item set rules just like in the demo, i dont get it why it disables it when other item equipped. Because for example the gun that being picked can work with left hand grenade when you spawn, but after this func run it uneqips left hand grenadeWithout stepping through the code it's hard to say, but my guess is that you could have an ItemSetRule which prevents the ItemSet from being active when the item is added to slot 0.