Just had a conversation with my Zoom rep. It appears there is a known issue with certain revisions of Realtek hardware in HP/Dell and Microsoft systems. The Zoom software has trouble communicating with the hardware in order to properly handle background noise suppression. The result is the Zoom software mutes the mic or locks the microphone hardware requiring a reboot.
Zoom is working to write code to be able to properly suppress background noise and adjust from low/medium/high or even disable to help with these issues. It's supposedly scheduled for inclusion in Version 5.4 of the Zoom software. Unfortunately, there is no ETA for release.