When you dont see me and pincer

I have it logged somewhere if you need it, but I was fighting Hafizar when I was affected by when you dont see me. Through -str I dropped one of my axes so I was only wielding one, then my pincer command went through and I got the You try to pincer some empty air near Hafizar or whatever it is. Just thought it buggy that you can try to pincer when you only use one axe and are affect by when you dont see me, but you can't even attempt to when you arent affected and only have one axe.