Droning noise after tire rotation and CVT fluid change

I have a 2016 Civic EX-T sedan and just took it in for an oil change/checkup at 50,000 miles (I know I'm racking up the miles quick). I had them change the oil/filter, rotate the tires, and also change the CVT fluid since it seemed like it was due (based on the dealer opinion and some internet searching I figured it couldn't hurt).

Well about a week after I got it back I started noticing a constant droning sound at speeds above 30 mph, loudest at highway speeds. It sounds as if I'm driving next to someone with a crappy exhuast. It doesn't seem to be coming from the engine, and the pitch changes with vehicle speed but NOT engine speed.

Could this be something with the CVT? I don't hear it when I rev the car in park and it's difficult to pinpoint where the sound is coming from but it's just a constant droning noise that gets higher pitched the faster I go. I'm wondering if it's the CVT or a wonky tire. Maybe I have a rock stuck in the tread. Any ideas?

Thanks!

Your tires may have some uneven wear, feathering of the tread on the inside and/or outside edges. The two rear tires were moved to the front and are rotating in the opposite direction now.

There may be some tread noise which would change pitch with changing road speeds.

My instinct told me it was tire related and not CVT related, thanks. One thing I didn't mention, which now seems super obvious, is my front right (now rear right) tire is much newer due to a puncture in the old tire. So that tire has 9/32 tread compared to 7/32 tread on all the others. That might be the answer right there. Is that enough to make a sound like the one I described?

I should note that front right (now rear right) tire was replaced in January in a pinch when I punctured it on the way home from work in a snowstorm and barely made it to Tire Discounters before they closed. I didn't notice the sound when it was at the front, but the weight of the motor may have evened it out a little more and the front left wouldn't have been as worn. I was planning to upgrade to a whole new set of 4 tires this fall but I may want to accelerate that decision now.

check if the fixed the protection panel under the engine properly.

I rotated the rear tire back to the front and the sound still seems to be coming from the rear. Taking it into the dealership this weekend to try to diagnose the problem. Sounds like it's a vibration somewhere but I have no idea why I would start noticing it out of the blue a week after getting it from the shop.

Just to close this out in case anyone comes across this issue again, it was a bad wheel bearing in the rear. That was the only thing left I could think of. It was fully covered under the powertrain warranty though, so no harm done!