A co-worker didn't answer back in time for the original answer; but I received his email today.
Seems he actually came across a printed reason though I have not yet taken the time to look at it myself - so take this in the same vein as it is offered - for free!
Your guess is correct; according to the folks who print the DOD plates, it is a printing “anomaly”. The second page of the DOD FLIP chart, under “Special Notice”, dated 13 November 2014 explains the dashed runway profile issue.