Having experienced this same issue with my Plantronics bluetooth headset on a Surface Pro 3 with Windows 10 Professional, I may have found a solution...
Select the Audio Settings in Zoom. There is a "Sync buttons on headset" option. If it is selected,deselect this option.
You may also need to check with the Zoom host that they don't have an auto-mute attendees option enabled.
Let me know if this works.