Mine hole and stone collum

[Zodiac215]

I built an mine hole and before i knew the stair provided a little safe zone a built an stone collum two tiles away from it, when i learned about it i destroyed the stone collum and there was a lot of falling bounders in the area, is this interaction correct?
Here a print screen: https://imgur.com/a/T1gC7JT

[MagicManICT]

Any time you break a support structure, and there are unsupported tiles that are unstable in the radius, there will be a cave-in. Did you build the other column, the one pictured, before or after you destroyed the one you mention in your post? If after, it could have happened from a variety of places. If after, it shouldn't have as I understand it.

There have been other posts similar to this. I've not seen a definitive answer on the issue as of yet.

[Zodiac215]

the column on the picture was there before i destroyed the other one, i knew about the unsuported unstable tiles but they looked all protected, as the red circles show.

Here a picture with a mark where the destroyed column was: https://imgur.com/a/vJ2Pxg2