Ah, I presumed it was the same as in practice mode, which definitely doesn't act like that. Do the drones spawn in a particular order(the different colored ones that do different things when gadget characters use them)? And what do you mean they usually spawn in that order? If it's usually, rather than always, that's a random element to it?
Also, I'm pretty sure they don't just move back forth, at least not the way the roomba does. The Roomba has a set range, it always goes to the edge of that range and then turns around. The drones don't seem to do that, at the very least their range is less obvious.
Fuck it. I'm going to have to go test for my self. Sucks that I can't use practice mode