Kimo's chewing and eating habits

I notice that Kimo likes to chew on his chew bone when I'm sitting in the back reading. But when I go back into the house, he stops chewing. Can't figure out why that is.

Maybe it's related to his eating habits. He generally won't eat his food until I come out and watch him eat. Unless it's something really tasty like chicken jerkey or certain dog biscuits. Maybe it's because I trained him to sit down and wait first before he can eat. Unintended consequences.