When you allow a student or group to re-hand-in, the group's old hand-in will effectively be deleted, and feedback can no longer be given to it. Any feedback that was given to the old – now replaced – hand-in will have been given to a deleted hand-in.
The feedback given to the deleted hand-in is still available in the system and counts towards the number of feedbacks the giving student had to make, even though it was given to a hand-in that is now deleted. A small icon will show in the interface next to feedback that has been given to a deleted hand-in.
Feedback given to a deleted/replaced hand-in will not count towards the receiving student's hand-in score – only feedback given to the most recent hand-in for that student will count towards the hand-in score. However, the feedback given will count towards the giving student's feedback score.