How to diagnose user permission change failures? ,
Check "Take authorized caller actions" arbitrarily punch in a caller id number
Says it was successful
Go back to user account, the update data is unchanged (should be today, 9/2/2020)
Clicking "Edit" pencil and re-editing, sure enough - the new permission was not applied.
I have tried a half dozen times with different caller id numbers. I've also updated several other users just fine, so it appears to be something specific to his account.