Card ownership or "control" keyword glitch
In a historic standard match there was an instance in which one of my creatures was enchanted by the opponent player with Mirrorhall Mimic transformed with its disturb cost, this card read as follows:
"Enchant creature
At the beginning of your upkeep, create a token that's a copy of enchanted creature, except it's a Spirit in addition to its other types."
The use of this enchantment aura on me makes it act more like a curse, yet when hovering over the card on screen it still listed is as "Controlled by [opponent's name]".
In response to this, I cast a Debt to the Kami instant spell which had two options but should have done the following as the card reads:
"Target opponent exiles an enchantment they control."
And as this curse/enchantment was the only one in play it should have been removed but for some reason, nothing happened and it continued into their next upkeep whence they created a copy of my creature as if nothing happened.
Personally, I'm not sure if I am misunderstanding who holds control over the enchantment once it's played unto another player's card but regardless this glitch is either one of the game recognizing who controls said enchantment(as listed when hovering over his card, similarly to my own lack of clarity), OR a bug over not recognizing cards an opponent controls when they are on the other side of the battlefield for triggered actions in a spell(as listed on Debt to the Kami's ability).