Apple finally replaced my right ear bud. This is actually a design/engineering problem. Some pointed out on Reddit that the black mesh on the ear bud may be protruding more that it should. This was in fact true for me. The mesh protrudes more on my right earbud compared to the left. As a result, whenever I try to adjust my right I’d hear a loud noice like a microphone brought close to a speaker.
I would contact Apple or take them to an apple store. If you mail them in, they will most likely be sent back to you because they may pass all the test unless the technicians wear the buds, which I doubt they do.