Can you explain the unusual routing of this registered postal card in 1941 during the WW2 occupation?

15 Rpf.
foreign surface postal card rate

 + 30 Rpf. registration fee

Luxemburg 1, 18 January 1941

Reich censorship in Berlin or Frankfurt

San Francisco, California (West coast of the United States!) 3 March 1941

Union City, New Jersey USA (East coast of the United States) 8 Mar 1941

The card is incorrectly addressed to “Union-City N.Y.” but was delivered to nearby Union City, New Jersey.

There is also a Union City, California, on the east side of San Francisco Bay. Might that have been why the card reached San Francisco, California on March 3rd? The postal clerks certainly haven’t given us any clues!