I see what you mean. The "Add a block" is showing up on the sub-page as "the feature" of having editing on for course administration. But on sub-pages..."course admin" is seldom needed...just the editing of the assignment or quiz, etc. And the "add a block" just gets in the way.
So...yes...having course admin editing turn off as the default when entering a sub-page is what we want.
On the flip side, we would like "course admin editing on" as the default whenever entering the main front page of the course as the instructor.