Aeon Men and Sky Deck?

So I was playing Oblivaeon and at one point in phase 3, I noticed that Oblivaeon started playing Aeon men from the Oblivaeon deck.  Checking his deck showed that a few Aeon men were in his deck.  Not exactly sure how they got there, but I do know Sky Deck was in play earlier and Aeon Men were getting destroyed.  They’re supposed to go to the bottom of the Aeon Men deck, though, right?

Is this a known issue?  Or is there another way Aeon Men could appear in Oblivaeon’s deck?

Sorry, iOS, so no logs.