Hey there! So from your images I assume you have a fluid domain as well? In that case, your 'zone 19' must be connected to a conductive zone which would either of your positive or negative zones. If you did provide it correctly and the issue still persists, then that is because fluent has created a 'shadow' of your zone 19 and that is the one which is connected to either one of your conductive zones. You'll therefore need to specify the zone 19-shadow as your electrical connection rather than zone 19. 

Hope this helps! Cheers!