"cave in" inside mine support radius

[ozbourne79]

hello ,
yesterday i was mining my way between two parts of a cave by placing mining supports at the edge of each other. that was wrong to do i know but just two tiles before the edge of the last mine support a cave in occured. The mine support was whole, it didnt suffer any damage or destruction.Also the center of the tile i was mining ,was inside the mine support's radius.
https://ringofbrodgar.com/wiki/Mine_Support this is the relevant wiki page.
to be more precice:

https://imgur.com/a/ACWm8JI

and here are some screenshots from the incident:

https://imgur.com/a/JT0ZyYv

https://imgur.com/a/cdu8ubK

if i did something wrong please let me know. but i think it is a bug.

[vatas]

Doesn't look like you went past the three edge tiles as seen here: https://ringofbrodgar.com/wiki/File:Minesupport2.png