WoW WOTLK Classic

• Addon version: 10.0.16
• Server patch: 3.4.1.49822

For a while now if i loot something or get something from a quest, the items are not shown in the bag until i click the sort button. After sorting the inventory the new item appears and flashes like always. Is it possible to fix it, that the items are shown in the bag right when i get them, like before?
Is it a Bug or is there something wrong in the setup?

Thanks!