Major Description
Currently the ExternalUser.getProperties only exposes single value properties (or in case of multiple values in the LDAP only the first value). The problem is the code LdapIdentityProvider.createUser() (https://github.com/apache/jackrabbit-oak/blob/trunk/oak-auth-ldap/src/main/java/org/apache/jackrabbit/oak/security/authentication/ldap/impl/LdapIdentityProvider.java#L711). This only uses http://directory.apache.org/api/gen-docs/latest/apidocs/org/apache/directory/api/ldap/model/entry/Attribute.html#getString%28%29 which returns the first value only. One has to leverage the iterator implemented by each attribute object to get all values!