Inconsistent Noise Cancelling with AirPods Pro (2nd Gen) in quiet environments

Hi!

When using my AirPods Pro (2nd Gen USB C) in Noise Cancelling mode, if the environment is silent except for a constant white noise (like an air conditioner, dryer, or even a kind of constant road noise from outside), one of the AirPods randomly starts to reduce noise a lot less.

It's weird, like if one of the two AirPods (left or right) randomly switch to a mix of Transparency and Noise Cancelling, but 30/70%. Sometimes it's more "Transparent", sometimes a bit less, but it's very noticeable as you go from a "complete" silence to "one of my ear hear something more than the other".

The behavior is the same whatever the platform the AirPods are connected to (MacOS, iOS, Apple TV, Windows 10/11), and it's pretty frequent, like if there is such "constant background noise" (that is perfectly cancelled when the bug is not there), it happens every few minutes or so, sometimes less, sometimes more (I suspect it depends on the background white noise).

Sometimes, producing a very "variable" sound fix the issue temporarily, like hitting the floor with a piece of plastic or strongly shaking maracas (yes that's very specific :D)

I tried every available options, every reset procedures, I also tried a factory reset on my iPhone (just in case), I even got replacement AirPods for this issue, but this didn't solve it. I did a full investigation at a Genius Bar, with nothing detect as faulty on Apple side. But the problem is very real :/

AirPods are running latest firmware: 6F8 (but the problem is there since a few firmwares, maybe even since the release of the AirPods Pro 2)

Am I the only one experiencing this issue?