The editor on quiz questions changes after save. Process:

1.Select editor in the global config (TinyMCE)

2. Reload quiz question page and new editor shows up (TinyMCE)

3. Click "Save and Close". The editor switches to another editor (Not TinyMCE anymore). 

4. Reload the page and the global config set editor is now back (TinyMCE)

5. until I save again . . . and is back to a different editor (Not TinyMCE anymore). 

Here is a video outlining the issue:

https://www.youtube.com/watch?v=WdSlCJ9UFWQ