So I stumbles across a bug where we are no longer able to smelt or cook any items in a furnace the furnace looks like its lit but it wont smelt or coock any item inside.

When I relog locally and a fuel item is inside the furnace it consumes the fuel item and lights the furnace. If I then break the furnace and replace it on the same spot it is still lit. Very rarely the smelting does work on a spot which had no furnace before altough I do not know what causes this.

The problem started occurring after enabling a custom datapack but it remains even though the pack is no longer in the world. The vanilla datapack is also enabled.