Hi Frank,
I created that issue earlier today - I hadn't considered then that maybe the colon shouldn't be there at all in the Simple dictionary format.
As you say, the displaced colon problem in MDL-27343 is theme related and occurs also in the Continuous without author format where the colon itself can be justified - though not essential in my opinion.
If no one has a justification for the colon after the concept, I'll create a new issue tomorrow.
Cheers,
Glenys