I just got WF-1000XM4.

When I connected it to PC as well as Mobile and tested conference call(MS Teams and ZOOM), I hear noise similar to fans or as if I am in a Tunnel.
It doesn't bother me too much while talking but I don't think that is normal.

Hope it gets fixed.

Also, this might be MS teams or my phone issue, MS Teams on mobile I was not able to hear what other person said. There were no sound coming from the other side. It was similar when I chose "Headphone" rather than "Headset" on PC MS Teams device settings. FYI there aren't the same settings on the mobile version of Teams.