Unless the juice is somehow conductive at vaping voltages... or some component of its flavoring.
I'm aware that you're talking carto tanks, but is there a chance you have a clearo lying around? You could check it's resistance dry, then fill it, vape a while, and see if it changes, too. That would pretty much confirm that the problem has something to do with the particular juice... and if that's the case, some email correspondence with the maker might be in order. They may not be aware of any problem.