I’ve just reached out to AdRev myself about this to see if authors can opt out of having their music put into AudioSwap. Obviously this doesn’t affect non-exclusives but could well indeed contravene Envato’s own rules with Exclusives.
That said, making our music available this way isn’t related to licensing (ie. exclusives can’t license their music elsewhere) and Envato allow Exclusives and non-exclusives alike to sell our music via iTunes, Bandcamp etc - so it could well fall under those terms.
I’ll report back when I hear something from AdRev on this.