Is Octo supposed to be braindead when you're not near it?

I've found that it varies by situation. That one at newties I'm familiar with, and it's pretty annoying. In particular, Octo won't attack HT's left head at all if you put him on the top left platform. I would test him out in different situations to see where he does and doesn't attack to see how dependable he is. Generally speaking, he shouldn't be braindead when you're not near him so long as he exists to your client (so don't get so far away that he'd disappear from your mini-map if he were another person).