Nils Jönsson causes a lot of trouble in figuring out his genealogy.
The issue is due to him somehow ending up with another birthdate after he moves out from Allerum to Kattarp parish. I managed to match him due to the year of his move - 1838. Allerum says he moves out to Kattarp in 1838, and Kattarp says he moved in from Allerum in 1838.
His birthdate in Allerum is 19th of May 1815.
His birthday in Kattarp suddenly 15th of September 1815. The 9 and the 5 switch places.
However I am now confident that this is the same man, and this is why I've been merging the trees.
