This has happened to me twice now. I once climbed a ladder and was shot at the top. I lost all audio and the unconscious prompt showed but i could see my character through a dark filter and move him.
A second time in a house I was shot by a guy and went down (prompt shows) but once again I can see and my gun is readied. Guy walks into the room and I dont see any shooting animations through the filter (also cant use my inventory) but I pressed fire and he dropped dead so I think it let me shoot him even though I should have been knocked out :/. Eventually It just told me I was dead, in both cases I believe my legs may have been broken that is the only consistency.
No idea how to reproduce, both situations were quite different.