Yes, when you say, " (thus being remove from the group), the teacher can not see that submission." this is because the student and the teacher are no longer in the same group. This sounds like you are using Separate Groups in this course and Assignment.
As long as the teacher and the student are in at least one group together, the teacher will be able to see the student and their submissions.
So, if there any other groups in the course, make sure both the student and the teacher are in the group. If there are no other groups, you can create a single group and put everyone in it. That way the teacher will be able to see and grade all the students since they will always be in one group together.
As long as the teacher and the student are in at least one group together, the teacher will be able to see the student and their submissions.
So, if there any other groups in the course, make sure both the student and the teacher are in the group. If there are no other groups, you can create a single group and put everyone in it. That way the teacher will be able to see and grade all the students since they will always be in one group together.
Or, since this is your block, when your code takes them from restriction group, you could then move/add them to another group to indicate they are done, and make sure the teacher is in both groups as well.