"AirPods Pro Detected Near You" but impossible to identify them

Find My has identified "Unknown AirPods Pro" which are apparently following me. Looking over the red-dotted location history of this device, I'm fairly certain that these are my own AirPods because they have been tracking me along walks I've been on without a bag, car, or anything like that. They were "First seen" when I'd been at home all day, about 2 hours before I even left the house.

However there's no way for me to verify that they aren't mine. Both "Play Sound" and "Find" are unavailable, and "Learn More About This Item" just gets stuck on an endless loading screen.

I recently shared audio with a friend who also has AirPods Pro, and I recall that giving me a popup about the other user being able to see the location of their AirPods or something. I wonder if that has anything to do with this.

I've factory reset the AirPods and paused the notifications for today, but when I spoke to a senior advisor at Apple they really weren't sure what was happening. The device no longer shows up in Find My's Items tab.

Can anyone shed any light on this? Cheers.

*AirPods Pro 2 firmware is up to date, iPhone is running iOS 16.5