As of yesterday, I sent my QC53II back to Bose. Overnight the ANR stopped being as effective as it was when I first bought the set.
I haven't been actively updating the software, but either my wife or I did accidentally a few days ago. For info, I haven't been updating the firmware simply because I "plug and play" and don't tend to use the Bose Connect app. It's only when my wife started using them only a few days ago, that I used the App.
The ANR was so good before that I could work and not be disturbed.
My daily (lockdown induced walk) was bliss because I would put on the QC35II, and walk without being disturbed - listening to very quiet radio chat or music. Nothing would get past the ANR. I live next to a busy main A-road town bypass, even walking along that I would have to be very careful to keep a lookout for cars as I would not hear them.
Overnight, the ANR effectiveness was reduced. Wearing them around the house to work, I have noticed more ambient noise. When walking in the same places (daily walk remember) the ambient noise is much more pronounced - cars, footsteps and even bird song get through. Things that I have never experienced before when wearing the QC35II.
A poster mentioned above that it is likely (in their opinion) that people are jumping on the band-wagon after a minority of complaints. In my case, both my wife and I noticed a reduction in ANR quality and that then prompted my search for any reports and potential issues. Hence, I stumbled onto this thread.
I appreciate the amount of work that Bose and their Engineers have done to investigate and so far I have been impressed with the return and replacement policy. However, I'm dreading that the new replacement will have the same issue.
I take care of my headset, and it lives in the carry-case when not in use.
The cushions are in very good condition.
I have executed all the trouble-shooting advice to no avail.
The ANR toggle in the Connect app makes little difference when toggling from "low" to "high" ANR. "OFF" works, "OFF" to "low" engages ANR but essentially "high" makes very little difference anc certainly not back to the original ANR.
Is Bose still looking into this issue or is "case closed" and no further fault found?
(PS I can forward the S/N of the returned headset if required as well as the UPS tracking info if needed)