As Foretold/Channel Bug
So I had 4 As Foretolds on the battlefield (don't ask me why I had 4 As Foretolds on the battlefield) and a Saiba Trespassers in hand.
I waited until my opponent's turn to use the channel ability of Saiba Trespassers, but when I clicked on the card it gave me two "cast with as foretold options" in addition to the channel option (maybe channel/AF caused a conflict somehow?), and when I tried to channel it the card appeared on the stack but didn't tap mana and wasn't actually on the stack (the opponent continued with their turn).
It was stuck in the area of the stack until I clicked on it and it let me pick how to cast it again (but still wouldn't work properly). Ignore that I don't have enough mana in the screenshot, I activated midnight clock before taking it but after the actual bug happened.