Are you able to check the site permissions for GoToMeeting while in session (padlock icon) ? See if you can toggle these to allow the use of microphones permanently.
I kinda did the cardinal troubleshooting sin and did multiple remediations at the same time. I reset Chrome (couldn't hurt to clean it out). I also reset Pulse (also couldn't hurt). I also decided to update the Kernel to 5.3. So far it's working, but I need to stress test some more. I'm also trying out the Vivaldi browser.