0xC0DED0D0 I have the same behavior on a Pixel 9, and heard about this problem on different Pixel models.
So I think it is a software bug rather than hardware bug, because I assume that the different models have different microphones and speaker architecture.
The pop sound is somewhat like on old stereo systems when you listen over speakers and put a corded headphone into it or pull it out, than it gives this loud pop sound.
Can't explain this better, it sounds like an interference, as if each browser window is set to highest volume for a split second, even when the browser window is muted.
And you only hear it when video or audio is played by another window or app at the same time.