Dirt blocks appear suddenly after rocket returns

Are you sure you don't have algae or slime up there that get's heated up by a rocket exhaust causing it to turn into dirt?

At first i though something like that was occurring, so I decided to watch that spot directly after the rocket lands and the dirt blocks just appear suddenly at that spot out of nowhere. Infact, there was regolith blocks above it over the bunker tiles during that time and they too suddenly changed to dirt blocks. So i assume this has to be some kind of bug.

something is being cooked, probably below the insulation tiles (near the base of the rocket?)

When algae/slime is cooked into dirt, the dirt appears in the first free tile in the UP direction.