Column reference "xxxxx" is ambiguous in case of exposed filter

Hello,
I have a very simple view which lists students and their personal data. It has only one relationship to the content profile page of users. I added a dropdown exposed filter (Content: Kar (field_profile_s_faculty) - Allowed values) to narrow results by faculties. Whebn I try to narrow the result with this filter, got this error message: warning: pg_query(): Query failed: ERROR: column reference "field_profile_s_faculty_value" is ambiguous (...)
This view creates this SQL:

SELECT node_users_node_data_field_profile_fullname.field_profile_fullname_value AS node_users_node_data_field_profile_fullname_field_profile_fu,
node_users.type AS node_users_type,
node_users.nid AS node_users_nid,
node_users.vid AS node_users_vid,
users.name AS users_name,
users.uid AS uid,
users.mail AS users_mail,
users.created AS users_created,
field_profile_s_faculty_value AS field_profile_s_faculty_value,
field_profile_s_type_value AS field_profile_s_type_value
 FROM users users 
 LEFT JOIN node node_users ON users.uid = node_users.uid AND node_users.type = 'profile_page'
 INNER JOIN users_roles users_roles ON users.uid = users_roles.uid
 LEFT JOIN content_type_profile_page node_users_node_data_field_profile_fullname ON node_users.vid = node_users_node_data_field_profile_fullname.vid
 WHERE (users_roles.rid = 6 AND (node_users_node_data_field_profile_s_faculty.field_profile_s_faculty_value = 'GTK'
   ORDER BY node_users_node_data_field_profile_fullname_field_profile_fu ASC

If I added the same field as a normal exposed filter, it works correctly. The SQL is slightly different:

SELECT node_users_node_data_field_profile_s_faculty.field_profile_fullname_value AS node_users_node_data_field_profile_s_faculty_field_profile_f,
node_users.type AS node_users_type,
node_users.nid AS node_users_nid,
node_users.vid AS node_users_vid,
users.name AS users_name,
users.uid AS uid,
users.mail AS users_mail,
users.created AS users_created,
field_profile_s_faculty_value AS field_profile_s_faculty_value,
field_profile_s_type_value AS field_profile_s_type_value
 FROM users users 
 LEFT JOIN node node_users ON users.uid = node_users.uid AND node_users.type = 'profile_page'
 INNER JOIN users_roles users_roles ON users.uid = users_roles.uid
 LEFT JOIN content_type_profile_page node_users_node_data_field_profile_s_faculty ON node_users.vid = node_users_node_data_field_profile_s_faculty.vid
 WHERE (users_roles.rid = 6) AND ((node_users_node_data_field_profile_s_faculty.field_profile_s_faculty_value) = ('GTK'))
   ORDER BY node_users_node_data_field_profile_s_faculty_field_profile_f ASC