I had a brief chat with a friend today who recently hiked in to Deep Creek via the long way from Mojave Dam. Him and his girlfriend hiked out right when the sun went down. They had good headlamps, and right at sunset and as it got darker they saw a good size mountain lion following them. It was crossing the creek a few times and keeping its distance but definitely getting too close for comfort. They didn't panic or run fortunately, but threw rocks and waved their towels high over their heads to look bigger. That seemed to scare off the mountain lion.
So just be aware when hiking to Deep Creek, especially if you come in that long way.