In the MySql prompt on the NFA server, in the reporter database run the following:
select * from user_definitions where username = 'NameWithNULL_in_bind_users'\G;
In the MySql prompt on the PC server, in the netqosportal database run the following:
update bind_users SET PermissionItemID = <ID> where UserName = '<userName>';
After this the NFA Data Source synchronized successfully.