I've spoke with Customer Care and they were able to replicate the issue but didn't have a solution for this issue. Whenever a caller joins via phone (computer audio is not affected), the hosts/organizers all have their GTM panels open and take focus (haven't tested with participants), meaning that any thing that was being shown (ie. PowerPoint, video, etc.) now no longer takes input from the keyboard or a clicker. We are running various versions of macOS from Sierra to Mojave but all experiencing the same issue.
Hi @rich012, welcome to the community!
I just tested this and see what you mean. I will dig into this more and see if I can identify why phone callers trigger this behavior.