Unable to build/pave/flatten/affect "stone" tile

[CallmeKek]

Hi, hello. I'm trying to build my palisade and tried making my entrance on this here stone tile that is naturally occurring.
For some reason however, it doesn't let me. Even if everything is flattened according to the tile.
So I thought, maybe I can circumvent this by clearing/paving/flattening/mining this tile... Nothing works.
If I mine this one tile, it seems that I can just infinitely mine it without anything happening to it. I just get infinite stone.

So I talked to some fellow Heartheners about this and it took them by surprise as well, since building a bunch of palisades and gates on a mountain is no problem.
I've tried everything that makes sense, but I can't find a solution. Is this intended? Is this tile supposed to be completely impervious and unable to be affected? I genuinely can't tell if this is a bug or a skill issue.

If anyone have any ideas, I'm open to hear and try them out. I don't want to have to get a claim flag just to extend and build around one small strip of stone tile.