Honestly there only thinking of themselves not the community that plays the game. They need to do a vote on this not be like hey lets ruin the tribe that are built in a cave that never had the no build part since day one!!
BRO I agree if your read it it says (Last week we encountered a bug that rendered some caves build-able. ) its been buildable since day one and did not have the mission symbol and like u said no mission near that cave at all!!