I've definitely noticed a difference, in that I can hear the hum of my desktop computer, where it was almost completely inaudible previously. Perhaps Apple could introduce tuning/options so folks can set their desired level of noise-cancellation?
Take a recording of the hum of your desktop computer by setting an iPhone next to (ideally, on a towel or pillow) your computer and using Audio Memo to capture a clean recording of the hum.
Then open an AppleCare support case and indicate that your AirPods stopped noise canceling a certain hum in your house a few weeks/months ago, and that you'd captured a recording of that hum with an iPhone and would like Apple to evaluate whether your AirPods are defective or the hum is by design found not to be addressed by their noise canceling.
At the very least, they'll probably let you provide them the recording (Support has a way to capture files electronically), and at best, they'll either execute a capture/swap of your AirPods for testing or tell you that this is within expected tolerances but thank you for the recording in case it helps them improve in the future.
This is a good opportunity to recommend Sennheiser PXC 550. They allow you to customize noise cancellation to your liking. There are other good things about them, and after trying Bose QC35 and PXC 550 for about a week, it wasn't a difficult decision to make. I've had them for >2 years now.
Is this not also maybe some weirdness with ANC? I have a solid pair of active noise cancelling cans (they're a hybrid in-ear/over the head setup) and they they're definitely inconsistent in what they filter out.
At home I could whistle and click my fingers and it would all be filtered, I was completely separated from body and mind as far as hearing went. As soon as I got on the tube, things started leaking through.
(I don't want to advertise, I just bought these cans on a trial/subscription basis, so I could feel them out for a month or so in the wild with minimal risk.)
Also! Test your ear tip fit again, in case they changed the algorithm. I recently had to change ear tips and maybe that’s why. They’re so much better now than they were before the update, too.
