Hissing sound / noise in left airpod ONLY in Transparency and Noise Cancellation modes
I have been using first gen Apple Airpods Pro which I bought in Sep 2020. Lately I noticed that whenever I toggle either Noise Cancellation or Transparency mode, I hear a sharp hissing sound coming from the left airpod. If I tap the left airpod, the hissing sound stops briefly for a moment but starts again soon after. The airpods work fine in the normal mode, audio/microphone quality and battery timing is ok.
P.S. I have checked similar threads, reset the airpods multiple times as per Apple's guideline but nothing worked.