Even painted boxes warp
Warped boxes are irritating. The boxes in the photo are only about two years old. They were painted and assembled when I first got them, but they still managed to warp. As you can see, the middle portions shrunk away from each other until a space large enough for bee passage appeared between them.
Will the bees let this go? Of course not! It has turned into their entrance of choice.
There is nothing really wrong with this as long as a hive is strong. It gives them a second entrance and probably saves some bee energy because they don’t have to walk so far once inside the hive. It also prevents congestion at the main entrance.
The problem occurs if a colony becomes weak and prone to attacks by robber bees or yellow jackets. In that case, one of the entrances has to be sealed off so the bees can better defend the hive.