I don't associate it with corportate retreat (religious connotations were the first to string to mind).

But even "corporate retreat" makes me think of teambuilding or blowing off steam or maybe networking or brainstorming in a different environment - not particularly learning (though I agree things like teambuilding are a kind of learning, and there are probably some with some explicit teaching going on). Whereas "camp" seems to be pretty straightforwardly about teaching ("bootcamp").

(on the other hand, you may be able to get companies to pay more for something called a retreat than for something called a camp)