Act of Treason + "Your first creature gains" supports bug

Unknown

When I use Act of Treason on opponent's creature, I have no my creatures at the battlefield and there some my "Your first creature gains" supports on the field (I had Sword of the Animist/Call of the Full Moon), "traitor" gains all effects of these supports, there is all right.
But after end of my turn creature returns to opponent control, it will have all gained effects from my supports while I have no some my "first creature". After I summon some creature, it gains all effects correctly and "traitor" lose them as it should be.
I saw the same bug with opponent support: opponent had Brawler's Plate and only one creature on the field. After I control this creature, it didn't lose effect of plate, because there weren't some other opponent's "first creature".

Gun Bunny

Seconded.me too.