@AndreTOQU3 the logic of the perk_lose persistent upgrade is handled by the vanilla game where it will remove either Quick Revive or the latest obtained perk if QR is not in the perk list. Additionally, the perk_lose persistent upgrade is almost impossible to lose in vanilla gameplay. Sorry, but I won't help further with this. You're trying to modify existing behaviour to one that is significantly different than the one players are used to and I don't see the point of such modification.