BartK Your hand arch is too flat and your joints are collapsing. Go extremely slow and observe your hand shape. The knuckle joints should be the highest point of the hand and make a nice arch, and when you press keys the last joint of the finger should not collapse inwards.
@BartK I noticed that in my video recently, too. And I've been trying to figure how to correct it. It sounds like simple to fix, but it turned out more complicated for me. I may start a new thread on this topic. Thanks for point this out.