Ancestry’s ThruLines found the wrong (Swedish) connection for several of my DNA matches, through the wrong Maria Nilsdotter. But the error proved a plus, because the actual (Swedish) connection was a generation earlier than ThruLines would have looked!
Then I realized that the matches may also be related to me via a Norwegian line. So many of my DNA matches are related to two or more of my branches, thanks to post-immigration marriages (not common ancestry of the branches).