Bad Microphone On My Right AirPod

Hello there,

I have AirPods 2nd gen for 2 months. A few days ago, my right AirPod's michrophone quality broke down. I tested it and I saw that my voice sounds muffled for a few seconds, then sounds normal and after a few seconds it sounds muffled again then normal again...

There is no any phisicial damage or water contact. Also the left one has not any problem.

I removed the connection from all my devices. I reset my AirPods, iPhone, iPad. But there is still problem.

What can I do? Is the only solution is Apple Service?

Thanks...