It appears to me to be frustration. I've noticed it on and off throughout the year. I can't remember which game it was (maybe the aTm game) but I remember Bo carrying the ball two times in row for dang good yardage on both carries then being pulled. There was a sideline shot of what appeared (and I stress APPEARED) to be him getting highly upset. The camera shot didn't stay on him to see the entire context of it, it was just a two second shot then back to play the camera went. However, there's no doubt Damien Harris has been very frustrated because there's been a lot of sideline shots of him being taken out after ripping off some good runs and his body language left no doubt what he was upset about.
which is perplexing to me considering CNS defensive mind and running plays eating the clock/gaining 5+ a carry.