I have that bug on Legion and have posted videos on Ubisoft forums reporting the issue there. They've said they've been able to replicate and are working on a fix. The glitching is there even when recording through the Xbox itself (as opposed to speakers or TV).
It's not the same thing as the little pops you hear sometimes in the Xbox UI when you get a notification or whatever. Those little pops have been there since the original Xbox One and don't happen in games.
Please do report the Legion issue to Ubi in this thread, the more people complain the more likely it is they'll fix it:
https://forums.ubisoft.com/showthread.php/2292856-Audio-Popping-Cracking?p=15247039#post15247039
You don't need to start a return request. The popping and crackling in Watch Dogs isn't tied to a particular sound effect: it happens constantly on the main menu, in game and in in-game menus too. The sound glitch is also different too.
You can go on Legion youtube streams and hear the glitching there too. Some people don't notice it when they're playing, only in the menus - but if you get the bug it's there all the time.