When I restart usually it just goes back into the "Center of hunting area" bug. And if I'm high enough level for the next area then it takes me to the next area. I'm fine with going to the new area because it will give better experience, but I'd prefer if I didn't have to interrupt the bot.
I check in with my bot every two or three hours when I'm away with teamviewer and I've caught the bot stuck and what a couple of times. But when I run into the error mentioned above I have to wait until I get to my PC to fix it since it requires a bit more.
What is strange though is that most quests have a "hunting ground" and it only stops on certain quests. I went from 35-43 without any problems today then it stopped in the middle of the Eastern Plaguelands during a quest. I restarted the bot and it moved me to Tanaris.
I am leveling a Troll Druid. My friend is leveling a Blood Elf Paladin and his HB has been non stop questing from 1-28 without problems. During those levels I had a lot of stopping problems. Getting stuck at a quest giver, bot shutting down due to full bags when I had 5+ slots left. Maybe it's just the way Trolls work?