A pilot asked me why the GPS said we were in Topeka when we were over Amarillo
So I'm elbow deep behind the panel of a King Air 200 last Tuesday and the pilot leans in and goes 'hey, why does the nav show Kansas right now?' I laughed thinking he was joking, then I checked the FMS and sure enough the position was 300 miles off. Turned out the #2 GPS antenna cable had a chafed spot near the wing root that was picking up interference, took me 2 hours with a scope to chase it down. Tbh it made me wonder how many squawks get written off as 'pilot error' when it's really just a bad ground somewhere, anybody else run into a ghost position like that?