[RLeeSimon]

Install "Mute." MNO Company-PlayStore
Go Convenience Key-Shortcuts-Settings
Turn on "Normal Profile" slider
Touch the word "Normal Profile"
Select "add"
Select "All Apps"
Select "Mute."
Back on out and it works like it did before

You can add 2 more functions to the "Convenience" Key which I find makes it INCONVENIENT

[RLeeSimon]

update; if phone is already ringing, does not interrupt... curses, foiled again... looking further for a better solution