I had a pre-divorce DL ticket flown back in June, and everything posted on schedule as expected.
DL did a nice job with it...my MP number was in the reservation, but did not print on the BP. One of the SkyClub agents said something about not having a mileage number in it, and I said I had my AS in there, and she looked somewhere else and saw it.
It seems that DL "locked" these pre-divorce reservations by hiding the AS number in there somewhere so it could not be altered.
I have about 3 more DL pre-divorce tickets yet to be flown, so we'll see if they post as seamlessly.