i first thought that this effect applies to artifact you CURRENTLY control. I checked the rulling.
"During the turn in which the "If this card is Special Summoned during your opponent's turn: Until the end of this turn, "Artifact" monsters you control cannot be targeted by, or be destroyed by, card effects." effect is applied, it is applied to all face-up "Artifact" monsters you control. (It is also applied to "Artifact" monsters that appear on your side of the field after the effect resolves, but it is not applied to "Artifact" monsters that are face-down or that are treated as Equip Cards.)"
I guess there were some coding issues.