I saw the same with my station, 681.
If I had to guess, I would say that lightning strikes reported from the US just happen to be coincident with the time of strikes reported in Europe within a window of a few microseconds. The servers can't tell the position of a strike except from reported strikes within the window, so it uses the time in the calculation, goofing up the position somewhat.
I'm surprised the data from the regions is not segregated in the servers to avoid this.
Don