My opponent had an enchanted Siona. It was power 3. I used Entrancing Lyre with x = 3 to tap it. The lyre goes on the stack and remains there without tapping the creature. I see the stack with the lyre on x = 3 for the entire game
Similar thing happened to me. Itried using entrancing lyre on a 2 power Stampede Rider, the trigger goes on stack but does not seem to resolve. Instead the phase shifts to combat because i dont have another play available. Eventually on my next turn moving into combat my opponents creature taps down after it triggers its own ability(this makes me believe it was a visual bug since a triggered ability going on the stack triggers a card animation updating the graphical state of the card). The original trigger of the lyre visually stays on the stack for the remainder of the game.
It also occured to me yesterday when playing a traditional draft game, which I lost because the creature that remained tapped was my last creatures, and I had a bunch of auras in hand, while my opponent did not have much to do and had an empty hand.
I had the same thing happen targeting a Sunmane Pegasus earlier. Trigger appears on the stack permanently. It clears if you alt-F4 the client and reenter the game.
This happened to me too. Lost a traditional draft match because of it.
Creature remained targeted by Entrancing Lyre after the Lyre was destroyed, which did not allow for the creature to untap for the rest of the game