I have seen some other similar location bloopers - but since I don't remember exactly what they were, I cannot search for them. Will have to note it down next time I stumble across one.
As for Y, Somme, Picardie it would be a kindness to the people who actually lived there to clean up the erroneous instances on wikitree. We cannot do much about the rest of the Internet ;-)
As for Sjulsson and a cluster of descendents with the same location error, there is an online tree in existence, showing a more appropriate location. One might even be able to source the family (in a while, when it won't confuse the readers of this thread).