I logged out closed the app, then logged back in and it stuck several times. The third time the settings reverted to Microphone 1 and Speaker 1. Nothing was changed on my laptop. The headset is plugged directly into my laptop. I asked two others in our company to test and they replied that their headsets were set as default, plugged directly into their laptops. They logged out, closed the app, logged back in and their Microphone also was Microphone 1 and Speaker 1.
Marty