I have the exact same grigri shown in the video, and somehow it never fails to lock when I'm quickly trying to feed slack to a leader and don't put a bit of pre

I have the exact same grigri shown in the video, and somehow it never fails to lock when I'm quickly trying to feed slack to a leader and don't put a bit of pressure on the left side. Even when I've added slack to the brake strand. I wonder if it has something to do with the angle, as it's pretty uncommon to have the climbing strand going straight up from the belayer.