How do I keep Notification Center on when displays are mirrored?

I have a standing desk that is very wide and has two keyboard trays. This allows a chair / sitting workstation on one side, and a standing workstation on the other. I have a an iMac at one workstation, with an external monitor at the other workstation. The iMac is mirrored with the other display so that I can quickly switch back and forth from standing to sitting without missing a beat.

OS X turns on Do Not Disturb mode by default when displays are mirrored. I know that there is a setting in the Notification Center preference pane to turn this off. However, every time I restart my computer, the checkbox that says Turn on Do Not Disturb "When mirroring to displays and projectors" is checked again, and I have to manually turn off Do Not Disturb.

Is there any way to stop this?