Auto-choose can sometimes tap artifacts which shouldn't be untapped at the time

With [[Necron Overlord]] just implemented, if you activate it for X = the number of untapped artifacts you have (including Necron Overlord), the auto-choose system will tap Necron Overlord as an auto-choice when it is already being tapped to pay for the costs of the ability. This doesn't appear to happen with static numbers of untapped things to tap when tested with [[Devout Chaplain]]. If the auto-choose doesn't kick in, Necron Overlord is correctly tapped by the time you're manually choosing untapped artifacts to tap.