For Compher, I would bet it was the Bennett hit. Compher really had hard contact on his head from the play, not that it was a dirty hit by any stretch. Did they do a concussion protocol at the time for Compher? I don't recall that they did, which seems strange in retrospect.
The Compher hit is one of the things that really bothers me about the current NHL. He took a hit and head contact, probably concussed, but the other Avs players didn't lose their minds, they just kept playing. It was a clean hit in my mind, so that is the way it should be.
Zadorov hit Bennett later on another clean hit and he loses his mind over being hit. Of course, it may have really worked out to the Avs advantage that he was so undisciplined, but I just hate how players get upset these days over being hit.