Hello Stephane,
Thank you for clearly detailing the problem, and showing an example of your settings. That helped me determine what is going on.
It sounds like you would want to set the”Heure es date de fin” to 2015-09-16. That field applies to the first event in the series, and it sounds like you only want that event to last one day. All of the recurences are based on that first event, so they will also last one day and start/end on the same time as that first event. So simply changing the field should fix it.
Does that all make sense? I wonder if we could make this more clear with some extra wording in the calendar?
Cheers!
– Brook