If I play Akshan Mischievous targeting my opponent's equipt Guardian Angel and my opponent reacts with Starcrossed, does the Guardian Angel return unequipt?

Here's the ruling based on the closest FAQ (#10576) and card texts I've checked.

Short answer: Yes, the Guardian Angel returns unequipped — it detaches from whatever unit it was on. But it goes to your base, not your opponent's, and since the control effect fails, your opponent still controls it there.

Why:

1. Star-Crossed resolves first, returning Akshan to your hand. He leaves the board before his trigger resolves.
2. Akshan's trigger still resolves (abilities on the chain are independent of their source). It tries to move the Guardian Angel to your base — and it does, detaching it from the enemy unit in the process.
3. The control-change ("You control it until I leave the board") can't stick because Akshan already left — the duration condition is already satisfied when the effect would apply.
4. The "attach it to me" instruction can't be followed (Akshan isn't on the board), so it's ignored.

Result: the Guardian Angel sits at your base, unequipped, but your opponent controls it since the control effect never successfully established. Your opponent can reclaim or re-equip it on their turn.