Me again...
So if I am a teacher on the frontend and I create a course - All I filled out was the name, category, course type = Non-Sequential and price = FREE guests, I published the course and received the admin email to approve it. All I did was approve the course and...
I received the Course Approved email to the teacher and the [AUTHOR_NAME] was populated in the template
I then went into the edit course information in admin and changed the name to now include "-WORKED" at the end so I could tell the difference between them and hit save. I then unapproved it and approved it again.
This time I got the "Course has no author. Send Email Error" message.
I went back to the frontend and edited the course information by only adding a couple of words to the description and clicked save.
Back in admin I unapproved and then approved the course again.
This time... it was approved again.
So there is something happening when you save the course information in Admin that is causing this error.
The correct teacher is selected in admin when you view the course information.
THEN I FOUND THE ISSUE
If you save the course information on the frontend as a teacher, it enters the USERID as just a number 123
If you save the course information in Admin, it will put | | around the USERID when it saves it to the database at |123|.
This is when it throw the error.