This is a completion step to
I don't think we want any mention of the assignment activity in the student's Timeline once the cutoff date has passed AND there is no group or user override enabling the student to submit.
This is how e.g. Quiz or Lesson or Choice work with the Timeline. Once the Availability / Duration end date has passed, they disappear from the Timeline whatsoever (There is an issue with suspended / not current users' Timeline for Choise and Quiz -
MDL-64238 - but this one, I hope, will be addressed soon.).
Currently, past assignments which students cannot complete do display in the Timeline under "Recently overdue", only stripped of the third "action link" line (added in 3.6). However, this is an exception that pertains to assignments only, while I think we should have one standard solution for all timed activities. I therefore propose that past activities that cannot be completed by students should be only viewable in the Calendar.
I will try to come back here with some screenshots to illustrate.