Reinforced tile border modified by mine_forward

[Steveleeb 1,067]

As you can see, the North West corner is to my left and is not reinforced.
However, when i mined forward it didn't give me a random slope on the north tile border, it gave me a random slope on the south, reinforced border.

If i can't fix it with concrete, the game shouldn't be able to screw it up with mine_forward
Im fairly certain this never used to happen. 

In english? .. it was flat before i mine_forward'd

Edited August 1, 2017 by Steveleeb