Plank no longer shows after time/date change

Plank version: 0.6.0.1023
Running elementary Luna with Pantheon

What happened: I changed the time and date in elementary system settings. Plank is set to autohide. I went to the bottom of the desktop and plank did not show. I went to a different desktop (ctrl+alt+right) and still, no plank. Alt+tab shows plank in the application switcher and is clickable, but still cannot show normal plank.

What I expected: The time and date will change and plank will be unaffected.

Resolution: 'killall plank' to restart plank. This should not be required. If this is the only fix, perhaps this could be included in plank's code such that on a date/time change it will restart.

Given that plank was still viewable in the alt+tab switcher, I wonder if plank did not crash but became inaccessible.