Same issue like was there
bug-when-digin-a-tunel-downward-t13416/?hilit=tunel
At entrance, I flat ground before stone wall at height 15. Then i dig Tunel upward - and entrance was made. Because there is iron right on surface I start mining instead of diging for next block forward.
When last 5% of material was left (scanned by probing) I switched to Diging downward to get deeper.
Results are - ceiling going down correctly, but floor remains on same level which results my head is inside ceiling and everything flipping around.
I made the same with next block - and results are same - ceiling goes down further more, floor remains flat - so next tile is even worse.
I think it is due combination of "mining ore" and switching to Dig tunel downward when block is almost mined out.
Printscreens below
https://onedrive.live.com/redir?resid=E206C6E155D617C2!3789&authkey=!ACXJimPW9JvCbzk&v=3&ithint=photo%2cpng
https://onedrive.live.com/redir?resid=E206C6E155D617C2!3790&authkey=!ABHdhKpJ-SX72U8&v=3&ithint=photo%2cpng