Well, apparently I ran afoul of the rules over on the OB forum and got a hand smacking ban. (They didn't tell me what rule, just "get out until we say so" who knows WTF I did). Anyhow, I cannot reference the thread about this over there but as I recall the noise is in the rear end of the OBXT. My own OB XT did this, hard turn, hard acceleration trying to get going and out of the way. Left turn as I recall. Many over there have complained of the same thing.
Mine sounded like a loud knock, knock, knock. A bit alarming, very noticeable. I went to an open and empty parking lot and tried to duplicate the noise, hard left from a standing start, and hit the gas. Maybe I didn't hit it hard enough (don't really like feeling like I'm intentionally abusing my car) but it didn't make the noise. Then I drove in tight figure 8's, trying to get it to do something similar. Didn't do it.
I was advised in the forums to see a dealer about it because "it'll only get worse" but I haven't brought up the issue to the dealer yet. I can see them drag this out for weeks and weeks before admitting there's an issue and then much as above, want me to wait for months until they get a part. Consensus over on the OB forums is it's in the rear diff or the center diff, not in the CVT. Maybe your problem is different but as I said, I cannot access the OB forums for the next week or so to compare notes.