Canasta - Give us the win if other people leave and we're already ahead.

When the opponent has left the game or is clearly no longer interested in playing the game (unless they are having a technical issue or personal issue that can explain why they aren't taking their turn) and the the timer expires but it doesn't populate the choice to extend or not to extend, what are you supposed to do? I have had many players run out of time to play their turn but instead of the EXTEND/DONT EXTEND buttons appearing, somehow, miraculously, they get a fresh timer and then they play. How are they able to do that? Is it just a glitch in the game? Because it happens more than you would think it to be just a glitch and is totally unfair.