Here's how the DNC is sorting them out. A party activist who follows these things e-mails:
Mithchell and Curtis are unpledged Distinguished Party leader delegates. Mitchell because of his service as the Democratic leader in the Senate and Curtis because he is a former DNC Chair. In years past both of them were registered voters in Maine, so they were part of the Maine delegation. For all unpledged delegates they must be a part of whatever state delegation where they are registered to vote.
This year as the DNC set out to confirm the states of legal residence for the Distinguished Party leader delegates, they realized that neither one of them are registered to vote in Maine. That's fine. Wherever they are registered to vote they will be considered part of that state's delegation. So Mitchell was moved to the NY delegation and Curtis was moved to the FL delegation (which of course has 0 delegates). This is not really that much news. For instance, it was learned that Distinguished Party leader unpledged delegate David Wilhlem was now registered to vote in Ohio. So he was moved from the Illinois delegation (where he was in 2004) to the Ohio delegation. This sort of stuff happens each cycle.