Sounds as though the 510 connector on the King
mod has either a bent 510 connector or the threads are messed up. Try another 22mm size atty on the king and see if it is the same. If it's just that one combo that messes up it may be what Eng's call a problem with tolerances. Tolerances are an allowed amount of mistakes in things. It may be that the two had mistakes that added up to cause this to happen.