Issue when multiple voters with same email address are introduced

When creating an election where the same email address is used for multiple voters (which is useful for testing), Helios does not complain. However, it appears that only one of the sent passwords is accepted, that is, only one password per email address is valid.

I guess Helios should either prevent introducing the same email address multiple times in the voter list, or should be able to manage voters that have different names but same email address.