Problem with the first empty item

In a content type, I have a multi value field of type "field_collection" [NOT required]
This field collection is made of 3 fields :
-Contributor: Entity ref [REQUIRED]
-Role: text list [REQUIRED]
-field3: text field [NOT required]

I am editing this field with the only possible widget for a field_collection field: Embeded

In the other hand, the widget used inside the field_collection for the contributor field is IEF complex:
- Allow users to add new Contributor.
- Allow users to add existing Contributor.
-No entity browser

To summarize, I am editing a field_collection field with the embed widget. This field is made of three fields, with the first one (contributor) edited with IEF

1-If nothing is encoded, I can't save the node because it complains about a mandatory Contributor field...

2-If I add a value for this field (Contributor (Kevin)+Role+field3), I can't remove it by clicking the "remove item" button

3-If I start with Kevin encoded as the first item then I add an empty item for the purpose of deleting Kevin, after clicking on the remove button for kevin, then the result is: Kevin is still there but the empty item is gone

4-If I start with Kevin and Nicholas encoded, then I remove Nicholas. After Nicholas have been removed, I click on the Add Item button. Instead of having a new empty value added, this is Nicholas which appear again. But this time, with an empty role...

I am using Drupal 8.2