Closed Unbreakable Dirt

Didn't see anything about this. Okay, so hopefully this picture can show what's happening, but some dirt is flying towards me because of digging a 3x3 spot, but two of the blocks did not fly towards me. They also happened to be the only dirt blocks with grass on them.

It also still shows the durability going down, which means it is noting that the dirt's being hit.

Edit: This could possibly be related to fire, because this planet sometimes rains fire. The coordinates are [-95150484, -86793907].