I wondered when there how long it's been since the current lake was part of the glacier (that said, some of the Patagonian glaciers - notably Perito Moreno - aren't retreating much or at all, because increased moisture is offsetting rising temperatures).
Did you get to see Cerro Torre?
It didn't seem like much of the glacier protruded into the lake. It was so dirty it was hard to see where the ice stopped and the rock/dirt started.
It was too cloudy/misty to see Cerro Torre.