If your experience is anything like mine they will make you go through a lengthy process to submit an iPhone log. After reviewing the log they will say there is no problem, they will try to blame the user saying it is “perceptual” (aka, it’s in your head or you are crazy), and they will say there isn’t anything else they can do. I would suggest running a ear tip fit check. Mine always fails the check once the ratting starts giving me an objective data point to refute the “perceptual” claim.
If you are lucky they will just offer a refund. They have no motivation to correct this problem and the engineers are clueless as to the source of the problem. This has happened to me so many times I kept a log of every time I used my latest set including what I was doing, what I was listening to, if I heard any anomalies, and whether or not they passed a fit check. When I offered these logs to the tier 2 rep that was coordinating with the engineer they refused to take them. This solidified the idea that they have no intent to fix the cause of this problem. Apple tells us they care about the environment, provide top notch support, and that these are somehow “pro.” Throwing replacement units at this problem over and over again while not trying to fix the underlying issue negates all of these claims.