The first thing I'd say is just "stop doing that." Arrive at the top, don't slam into it. Focus on pushing the floor away. Also, keep the bar on your skin and stay midfoot. As you said, you're getting forward.
But I based on this video, I wouldn't think these deadlifts would cause your knee pain. Did you squat during this workout? Do you have video of your squats?
By chance, were you the Huy living in Germany that called into the Call in Q&A a few weeks ago?