Just found this thread after a frustrating experience on the phone with Apple support in the UK for this exact issue (left has rattled for a while, right has just started). After 45 mins of checking the firmware and re-pairing the airpods the agent told me I'll have to post them in for service at my own expense and they will place a hold on my account payment method of £141GBP until they have inspected them in case it's something I've done and the repair turns out to be chargeable.
This can't be correct, surely? They're within the 12 month warranty period (bought from an Apple store) and it's bad enough that I have to send then in for an indeterminate amount of time but to try and pre-charge me just in case the issue is my fault seems crazy (I'm 100% confident that they have not been mistreated). Is this normal behaviour now? Shouldn't it be that I send them in and if they're faulty then they are repaired or replaced for free and if I've boiled them in the kettle or hit them with a 3 wood then they quote me for repair?
I can't even take them back to the store (90 min round trip) as no appointments are currently available and even if they were it's Manchester and I'd be worried about being able to travel there to get them back given impending lockdown.
Looking at my desk there are 2 x macbook pros, 1 x ipad pro with magic keyboard, 1 x iphone 11 pro max, magic keyboard and magic trackpad, I'm wearing an apple watch and my partner and kids both have loads of Apple devices plus we use apple TV and who knows how many of their services. You could say we've bought into the brand but if they're heading in the above direction for issues then we'll have to re-think that as one of the big reasons for having so much apple stuff is because of the previously brilliant service.