You aren't allowed to have empowered finisher + another finisher mod on the same class item anymore. You can manually equip the class item with it and it'll work but using it in loadouts will force an error code. To fix it: move the class item to another character (not vault) -> equip the loadout -> overwrite the loadout. If you want to keep the class item with the current mod setup then include another class item in the loadout and overwrite it. If you dont then change the mods then overwrite the loadout.