(I'm hoping I read it correctly)..maybe Lefty saw him as a threat to alpha status? When Kai and Kae have their disagreements over who's alpha, Kai always wins and after mounting him, he'll put his head over Kaedyn's as a way of saying "back off, I'm alpha".

I don't think it's ever okay to growl at the owner (in a mean way). When Kaedyn started becoming more comfortable after a couple weeks of coming home, he started challenging us and Kai. When he was going through this, he'd growl at me every time I told him to 'down'. And I don't let my dogs ignore me when I say a command so I wanted to enforce it by putting him in a down. I stood over him, and bent down. The moment I was at his level, he tried nipping me. He only got my lips and didn't break the skin. But now, he downs every single time and I think he is probably much happier letting Kai be the alpha dog. Of course, I'm the overall pack leader .