Adding to list breaks if duplicate entries

[quadrismegistus]

If I...

• create an empty list called Doctors List, with (e.g.) doctors marked 'physician' in Employments and Identifiers,
• then get the doctors marked 'physician' in Occupations & Posts (Group),
• and add those doctors to my Doctors List -- it won't work. No one is added.
• This is because the first doctor in the new list was already in my Doctors List.
• If I unselect the first two doctors in the new list, and try to add the rest to Doctors List,
• it will add the next 3, because they were not in the Doctors List

• but then break on the fourth, because he/she was.

Attaching screenshots to show. Hope this makes sense!

[epicfaace]

I think this should be fixed now. Can you check on staging to see if the issue still occurs?