Box set pick list items not deleting

I’ve combined a few box sets into multi-disc albums, leaving those box sets empty. In “Manage pick lists” those box sets now show 0 items. I’ve tried deleting them, but they don’t go away and still show in the pick list and in the dropdown when editing albums. I deleted them in the mobile app and they no longer show in the pick list there, but still show in CLZ web. I’ve tried logging out and back in, and closing out my browser and restarting, but no change.