[a-wu]

I've had my pair replaced for this too. It seems to be an issue with the NC mics. When neither NC nor Transparency are on, I didn't get the issue. Apple will do an Express Replacement (2-day new pair, _then_ you mail old pair back) which is nice.

[badwolf]

Mine got so bad I would get the "rattle" anytime music had any amount of bass/mids. Regardless of noise-cancellation or transparency.

[a-wu]

yikes, that sounds like blown out drivers?

[badwolf]

Possibly. It started out with just the "rattle" in noise cancellation or transparency mode. Then I started noticing it any time I talked on the phone/zoom/etc... (I have a deeper voice) then it started without the mic being used at all (NC completely off, just music or podcasts) ... Now the other pod is doing the same thing.

[Polylactic_acid]

Could just be some glue inside broke off.