I've always been of the belief that there is an Earth 1 Zatara and an Earth 2 Zatara. It never made sense that he "moved" from Earth 2 to Earth 1. If there can be an Earth 1 and Earth 2 Flash, Green Lanturn, Atom and Hawkman (and others of course0, why can't the same be true of Zatarra? (But now I wonder if there ever was an Earth 2 Zatanna.)