This has been an issue for several version, have now discovered the scenario to reproduce (I can do it every time):
1. Create an event, leave RSVP off/un-ticked (or use an existing event with RSVP off/un-ticked).
2. Edit the Event, enable/tick RSVP. Leave the default of 'Unlimited attendees' selected.
Now, the event has been automatically set to RSVP Limit:1 and only one member can RSVP
3. Edit the Event, you'll see that the event RSVP is Limit:1 (not Unlimited attendees)
4. Change the RSVP to 'Unlimited attendees'
... you'll now be OK and more than one member can RSVP.
1. Create an event, leave RSVP off/un-ticked (or use an existing event with RSVP off/un-ticked).
2. Edit the Event, enable/tick RSVP. Leave the default of 'Unlimited attendees' selected.
Now, the event has been automatically set to RSVP Limit:1 and only one member can RSVP
3. Edit the Event, you'll see that the event RSVP is Limit:1 (not Unlimited attendees)
4. Change the RSVP to 'Unlimited attendees'
... you'll now be OK and more than one member can RSVP.
