It’s my understanding this is a result of when a loadout has been saved during the introduction of the “shirtless” bug. You will need to change the item that is missing, to ensure the loadout is valid.
With the release of Update #9 (1.0.50) we identified an issue where the Zealot upper body cosmetic item, ‘Pious Mendicant’s Vestments’ was unintentionally removed. For those that had this item equipped the Upper Body slot would not show the cosmetic (making the model appear shirtless) and also allowed for all classes to also equip the item.
Today we will roll out a fix for this bug, meaning that players will not be able to equip ‘Pious Mendicant’s Vestments’ in the meantime. On Wednesday we aim to have the full fix in effect, so players can once again equip the cosmetic properly.