Weird lighting in Gravitas base

Update: It happened again and it doesn't seem to be because of damaged tiles (see attached screenshots, the tile isn't visibly damaged at least). My current belief is that there's some kind of bug triggered when the last square of regolith is removed from on top of the obsidian tile. I actually had a dupe fall through an obsidian tile earlier, shortly after a square of regolith was mined from on top of it; that could be related.

if you can next time on the tile that is doing this go to the properties page and see if the tile has 0kg of material