It could just be rare, but I don't think I've encountered it before. That said, I'm usually either knifing or getting counterknifed. Counterknifing someone else doesn't work that often for me.
Not sure but to me counter knife seems to happen more than before ( from both sides ) Once it felt like a counter on a counter and the fightds tend to take longer. Last time I tryed to counter, while on the ground, the other one steped on my knife hand with one foot .. and ..took my tag