My answer to the first was the asker's accepted. But after the merge the accept has been undone; most likely because it's another person's question.
An accepted answer tops the list of answers as a hint to other users that it may be relevant. Now that it's no longer the accepted one it may move all down the list.
I don't like the way this works, but I have no immediate solution. The question the other one was merged with could also have had an accepted answer. Maybe questions shouldn't be merged if they have both an accepted answer?