Did you ever get this resolved?
I had this same issue awhile ago also and took it into the dealer, they said it needed a new serpentine belt and per my request I had a drain and fill on the CVT at the same time, I noticed the problem was greatly reduced. That was about a year ago @ around 85,000 miles. I cannot confirm if they truly did a drain and fill - the dealership by me is hit or miss - but I think they did.
A little more info... I had the battery replaced because I was told by the dealer it was time to look into replacing the batter. So, I shopped around and got a battery that was well priced, changed the batteries out, and then... as I was driving to return the old batter, I had this irratic engine behavior going on with the A/C on. I got a check engine light after coming to a full stop at stop light. I can't remember the code, but it had to do with something electrical. That's what prompted me to take the car to the dealer. In my mind I thought the CVT was the culprit (which is why I requested the drain and fill on the CVT), but the dealer checked it out and said it was the serpentine belt. That makes sense to me since there was a new battery (new component to the electrical system), the belt drives the alternator (recharges the battery and critical to the electrical systems), and the compressor (which is why the a/c being on amplifies the issue).
I am noticing this issue coming back now. My car is just over 95,000 miles. I inspected the belt and it looks perfectly fine to me. I need to take the car in for the airbag recall and I am thinking about asking for a drain and fill on the CVT again. I do a lot of city driving so it wouldn't hurt anyways, but I'd love to know the root cause of this issue. Given my previous experience, I can't say it is the CVT, but I have read all around the internet that a drain and fill on the CVT is never a bad idea.
If the problem is still there, I'll try changing the serpentine belt myself since it is pretty easy to do.
Other thoughts I have had is:
- any of the pulleys attached to the belt could be going bad, including the compressor pulley
- Tensioner could be bad too.