Bitty Update: the point here is that Kent County is on the Eastern Shore, which is generally held to be unreconstructed conservative land attached to Democratically-controlled Maryland only by historical accident.
"E" stands for Early Votes ... (24th) ... stands for polling day.
Democratic primary voting in Kent County, Maryland:
Results before absentees (absentees typically have no effect in Kent Co. elections):
Anthony G. Brown & Ken Ulman E 182 (24th) 391 = 573 31.9%
Doug Gansler & Jolene Ivey E 126 (24th) 388 = 514 28.62%
Heather Mizeur & Delman Coates E 214 (24th) 448 = 662 36.86%
Mizeur did about 22% statewide, Gansler about 24% and Brown about 51%.
Not exactly a stunning endorsement from Democrats ... Maryland does not have open primaries.
Below the orange margin of error ...
I'm at a loss to explain this, other than the fact that Kent County is the state's smallest with a relatively large proportion of retirees from other places. A few votes either way make a big percentage change
The local Democratic Party organization doesn't seem particularly powerful here (the Republican bagger wing being noisier, anyway). The local elected officials don't seem overly biased toward progressive viewpoints, and in fact, elections to county office daw candidates who are only nominally Republican or Democrat.
It may be that college students from Washington College made a difference.
Anyway, I don't know the answer.