Please see other comments that are not indicated as under review that address a very similar problem that is a source of great frustration:
Feb 20, 2017. It is over 2 months since I joined my group and was given full access. Everything works EXCEPT EVENTS. From the first day I got the massage --"Your access to this calendar is being processed. Please check back later."-- It looks like your message is caught in a loop FOR ALL NEW MEMBERS. Old members say it works perfectly for them. PLEASE FIX THIS BUG ASAP. Our group is heavily dependent on scheduling.
Mina Erfani Marshall commented
We cannot see the events on the calendar, but do receive reminders from it. Is this a known issue?