Confirmed this bug is still happening to me. I checked the main screen and it says I have 1.0.3.0526 -steam. Remove a character from the party, Accept, go back to party selection, add character back to party, Accept, found everything in quickslots gone (didn't have anything in inventory but assume that would be gone too).
Generally, all I have lost is some consumables (scrolls and potions), but the wizard has lost 2 grimoires