Steps to reproduce:
1. Place a one-way left arrow.
2. Rotate it so that it's now a one-way down arrow.
3. Try to bash from right. Works correctly.
4. Try to bash from left. It's still being treated as a one way up arrow.
Not tested: Are flipped / inverted also affected?
This was a supported feature at one point (indeed, the intention being to remove the need for seperate objects for each direction).