Jira Service project auto-added customers

[AldoCauchiSavona]

I just reviewed our Support Desk Customers list and found two new customers.

Two questions based on the two circumstances.

Q1:

One is a company employee who was added in the Project settings > People. 

Is there some setting which indicates who as auto added to the Customers list, as we hav other company employees added to People with the same prermission, but are not listed as costomers. Maybe there's an LDAP group this other person is not part of, and so was added as a customer too.

Q2:

There is one other employee listed as a customer but I cannot find out how. Should I check his LDAP groups or see if JSM is configured to auto-add people on our domain as a customer too?

Thanks.