I am also having this issue (* along with a seemingly related issue). I bought the AirPods Pro when they first came out and experienced relatively few issues of this kind. However, a few months ago I got another pair of AirPods Pro to tag-team the workday, switching between the pairs when batteries drain on the pair I am using.
While the majority of the time the tag-team approach works, I figured my atypical use-case incited the issue described by this thread as I began to experience it on occasion. Over time, it seems like the issue has become more frequent, perhaps with the current firmware. It is harder to find more technical solutions for issues concerning AirPods dual-wielders like myself and it seems as though the Apple ecosystem is generally expecting users to have single pair associated with their account, not really expecting to juggle between two.
For the most part, my AirPods Pro are connected to my 2019 MacBook Pro but I certainly switch to my iPhone or iPad as needed, and I have had this issue across each of these host devices. The media I am listening to or watching would seemingly-randomly pause or sometimes (in the case of video) continue without producing any audio. When this occurs, I have caught the sound output settings in the menu bar displaying that it has briefly connected to the other pair in their case before disconnected (usually causing the pause to initiate).
(*) Other times, however, it does not look like the other device has connected. If I am watching a video in Safari, the whole tab seems to lock up in these cases. This makes me wonder if it is some deeper Core Audio or Bluetooth controller issue.
The issues occur enough these days that I was able to capture logs from Console.app streams as the issue occurs. There were a few points of interest worth following up on but have not had the time to investigate further.
I have tried the typical solutions:
- Forgetting the Bluetooth device
- Factory resetting the devices
- Cleaning the copper contacts on the AirPods and inside the case
I am now trying to enable "Automatic Ear Detection" but even if it helps I refuse to consider setting-dependent bug detours to be solutions for any product that does not function as advertised.
In general, I wish Apple devices had finer-grain audio routing rules. I had to remove the Bluetooth pairing with my car since merely connecting to a newly detected device implies automatic audio rerouting to that device, when it is not always desired.