I ran into a bug in version 2.14.1. Maybe the bug is not introduced in this version. The following is the problem. If I add an registrant to a event, then two entries of the same registrant are added to the event. If i do the same in the backend then everything is working fine. So I think this is a small bug in hour module. Can you fix this?
That's strange. Look like the form is duplicate submitted for some reasons. Could you let us know what browser you are using so that we can check it further?