I searched the tracker, I was sure I saw similar issue but could not find it.
When course has completion enabled and we there is a criterion that all/some activities need to be completed, teacher has to go to "course completion" settings every time after they add a new activity with completion criteria. This is both not intuitive (if you don't know about it) and annoying (if you do know about it).
Would be good to have better management of this situation. I understand that the course completion may be locked at the time when teacher adds the activity, this also complicates things.
1. When creating activity the "Activity completion" section may offer to add this activity completion to the course completion criteria.
2. When browsing the course page in the editing mode there could be an indication next to activity completion icon whether the activity is counted towards the course completion ctireria or not.
Definitely requires some UX team attention / mockups