Mining logic bug?

I had an area designated to mine, 32x32x5 or something like that. After a section of the area had a vertical section where only the 3 center blocks removed, leaving the top and bottom of the vertical pillar, no one mined that area. If I designate an area next to it, without the 3 center blocks removed, mining continues. If I try to mine the area in question, mining stops.
Steps to reproduce:

  1. Designate an area to mine, any size area with a 5 block height.
  2. Once 3 blocks are removed in the middle of the 5 block height, suspend mining so everyone leaves, then resume it. I didn’t do this but I assume they walked away to eat or sleep before they would return to mining so pausing and resuming should have the same affect.

Expected Results:
Designating to mine the affected area causes mining to stop.
Actual Results:


Attachments: (4.1 MB)

Version Number and Mods in use:
release-687 (x64). No mods.
System Information:
CPU - 2600k
GPU - 970 GTX