Are you using the Display.Church groups widget with a Pushpay/CCB integration? If so, you are probably opting to show the Registration status so your people know whether or not they can opt-in to the group.
Just to make sure you are aware…
The registration status will show as open under two conditions:
(1) The group capacity is unlimited.
(2) The members count is less than the group capacity.
Display, group widget, Pushpay / CCB, small groups