When an assignement is restricted to a gertain grouping, teachers (and also administrators) can only view submissions of students belonging to that grouping.
This behaviour can be a problem (is a problem for us) if you have, for instance, an assigment open to all students until certain date, and you want to extend the opening period beyond that date but only for certain grouping, so you make the assignment available only to this grouping for a while. While this second restriction is active, you cannot access the submitted files of the students not belonging to the grouping.
This is inconsistent, because as a teacher you can view, access and modify activities regardless of the currently active grouping, so you should also be able to access to the submitted assignments regardless of it.
Maybe there's a better way to achieve this goal, but I have not been able to figure it out.