AirPods mic problems

I have now on two consequtive sets of AirPods experienced the same problem. After a few months time, suddenly people I speak to tell me that sound from my mic is 'muffled' and very hard to hear. At first the problem is intermittent, gradually occuring on a larger and larger share of calls.

I learned recently, that disconnecting ('Forget this device'), resetting, and repairing the AirPods solves this. Only not for long; after a few calls it comes again, so in practice I need to reset multiple times per week. But at least that is doable.

Do others know of this problem - or a more permanent fix? I am on the latest firmware, and this is the second set of AirPods where the problem occurs...