It turns out there's an actual reason some owners of Google Pixel and Pixel XL Android handsets have been noticing microphone problems. Almost eight hundred people and counting have posted questions regarding this topic on Google's Pixel support forum. Google VP of Product and expert Googler Brian Rakowski confirmed with CNET that there is a snafu and it is a "hardware issue".
This of course means that affected devices can't be cured through a simple software patch. Instead Google encourages carriers of troubled Pixels to physically return their phones to receive a replacement under warranty free of charge.