Lots of dowsers experience this. Larry Stier called it a "stinger," Dell Winders had another name for it I don't recall, some dowsers just call it a ghost target. It's when you dowse to a location, dig a hole, and there's nothing there. The general belief is that it's caused by the real target somewhere else and all you gotta do is solve the relationship between the real target and the ghost target. I remember Larry had some real pretzel logic as he went from stinger to stinger to stinger, but never quite making it to a real target. In all honesty, it's just an alibi for dowsing failure.