offline XP is busted. you gain levels, but no stats, and max out at level 111 with -101905 xp to next level. on top of that, "item rarity" upgrade does nothing, i have every upgrade maxed except XP and ive never gotten anything but common drops.
loading the game up again fixed my XP to a valid number, but im still sitting with some 80 or so levels completely wasted. 1 thing you need to add : the ability to delete our saves completely. mostly so that when encountering game breaking bugs like this, they dont outright break the game permanently.