Spawned a black blob tile - Turned into a refined copper tile

Posted about it in the general discussions forum already. I've posted the link to the original thread.

A metal tile  (refined copper) was being damaged by over pressure from water. Instead of repairing I built some mesh tiles over it (iron ore) and a black blob spawned after the tile was deconstructed. the black blob showed up as 'copper' when I clicked on it. I then saved and reloaded the game and the black blob changed into an actual copper tile.

I've uploaded 3 save files:

Copper bug - after it happened. is the game with the bugged copper tile in it.
Copper bug - before it happened. is the most recent autosave before the copper tile appeared. The water is still over pressure damaging the tiles and I haven't deconstructed them yet.

Copper tile bug 1. is the same as copper bug - before it happened. But I deconstructed the metal tile that went buggy in the screenshots and 'copper bug - after it happened' save file. However when I did it this time, it was deconstructed normally and nothing happened.
However the difference is I used the 'deconstruct tool' only.
In the bugged save I built over the metal (copper) tiles with mesh (iron ore) tiles and the dark blob appeared after deconstruction.

Copper bug - after it happened.sav

copper bug - before it happened.sav

Copper tile bug 1.sav