Persons with an invitation can not sign up for an event

Hello to JEM developers.

I found a bug (I do not have much time to test it):
IN Backend:
If the creator sends invitations to the participants - all OK.
But, if the creator of the event wants these people to set up with the invitation as attendees - it does not work.
Event creator user must first delete the invitation and then we can set a participant atendees.

Hi,
I tried to reproduce your issue, but I didn't success:

In backend, I went to the attendees menu and added a user as invited and saved. He is on the list as invited (in FE and BE. He got an invitation email.
Then in backend, I choosed this invited user and clicked the button "add to attending". He is now on list as attending in FE and BE. But (that can perhaps be the problem he didn't get an email as information, that he is now on the list of attendings.

EDIT:
The invited user can go to the event and when he is logged in, he can answer as attending or non-attending. Then he gets an email that he is on the list of attendings.

I misinterpreted the problem, MY FAULT :

It's not a backend, but this error is reflected in the Frontend.

The creator of the event can not log participant who already has an invitation - at the state attendeed confirmation message pops up: 0 User (s) added

Yes, I understand now:
One thing is (for me it's ok: creator must be attending to get the door to the attending list!)
The other: there is no possibility to change from invited to attending or non-attending (FE attending list).
you must take a detour: delete the invited and add new the same person.

Yes, I write it in my first post.
But to tell the truth, it makes me illogical.

The creator of the event participants can log on and log off, but if the attendee invitation and logging it still has to log off and then log on again.

For my case, I would be for each user to log in, unsubscribe, or send an invitation. And for everyone to see a total listing of attendees and non attendees - this listing should be listed directly in proposition events (now there are only names registered.). Now only the creator of the action can do it. This is the theme for further development of JEM.

there will be a solution.