Biblio Editor mask behaving strangely

[LaviniaFerretti]

When creating a New Biblio entry through the Advanced create button, the Publisher section of the Editorial section of the entry mask behaves strangely.
If I add a Name or a Publisher for the Publisher and then click add, the entry appears twice in the mask.

If I then click on Save, the entry disappears from the mask.

However, it is saved twice in the xml (cf. joint screenshots).

Users can only enter the data properly by manually editing the xml file.