When doing a merge, you really need to pay attention to the data under "marriage" during the compare. Whereas, if there are parents, a birth place, etc. on one profile and not on the other, Wikitree suggests that the final profile have the parents, birth place, etc. with marriages it does not work this way. I have done the same thing a number of times. Not sure why it is designed this way, but, I remember from another question that marriage data is "stored" differently in the database.