Can I get some more feedback about my boss' strange behavior?

I know it may be a bit redundant to be talking about my job and my boss so often. But I’m realy interested in some feedback about this part of my life. I feel like this is one of the few places I can express myself and talk about what’s going on. So basically, this question is just a follow up to my previous question about my boss’ behavior. So today was really weird.
I was at work a few minutes in when I needed to go to the back to get something. And ran into my boss eating. I didnt know he was working today because didnt see his vehicle. I said “hello”. He said “hello“in the same tone. He sounded off guard. Then he awkwardly stopped eating a walked speedily out of sight. The a few minutes later we can into a similar area. Another coworker was talking to him.
There was an object in between us, so he could’nt see I was nearby working. Then the coworker pointed out that had food in his hair. He walked off from what he was doing and saw me as the coworker asked me to confirm that he had good in his hair. He looked embarrased. I didnt say anything. He ran off to the restroom. Then as I am working. He was moving about aimlessly in and out of my view. Until he disappeared. He just left for the rest of the shift. He even left his food right where he was eating. The was no indication that he left because of an emergency. It was so weird.