diff --git a/backend/tests/employees/test_department_role_ldap_sync.py b/backend/tests/employees/test_department_role_ldap_sync.py
index 194257cc..cc297aad 100644
--- a/backend/tests/employees/test_department_role_ldap_sync.py
+++ b/backend/tests/employees/test_department_role_ldap_sync.py
@@ -2,9 +2,12 @@ from types import SimpleNamespace
 from unittest.mock import MagicMock, patch
 
 import pytest
+from django.contrib.auth import get_user_model
 
 from employees.ldap.services.department_service import DepartmentService
-from employees.models import Department, DepartmentRole
+from employees.models import Department, DepartmentRole, EmployeeDepartment, LdapSyncState
+
+User = get_user_model()
 
 
 @pytest.mark.django_db
@@ -42,3 +45,58 @@ def test_sync_role_state_nests_role_group_into_department_group():
 
     assert fake_group.member == [role_group_dn]
     fake_group.save.assert_called_once()
+
+
+@pytest.mark.django_db
+def test_reconcile_department_group_keeps_members_and_multiple_role_groups():
+    dept = Department.objects.create(name="LDAP Dept Aggregate")
+    role1 = DepartmentRole.objects.create(
+        department=dept,
+        name="Reviewer",
+        ldap_group_dn="CN=ROLE_Reviewer,OU=LDAP Dept Aggregate,OU=Departments,DC=example,DC=local",
+    )
+    role2 = DepartmentRole.objects.create(
+        department=dept,
+        name="Approver",
+        ldap_group_dn="CN=ROLE_Approver,OU=LDAP Dept Aggregate,OU=Departments,DC=example,DC=local",
+    )
+    employee = User.objects.create(
+        email="dept-role-aggregate@example.com",
+        phone_number="+79990009999",
+        first_name="Role",
+        last_name="Aggregate",
+        is_active=True,
+        email_verified=True,
+    )
+    employee.set_password("pass")
+    employee.save()
+    EmployeeDepartment.objects.create(
+        employee=employee,
+        department=dept,
+        is_active=True,
+    )
+    LdapSyncState.objects.create(
+        model="employee",
+        object_pk=str(employee.pk),
+        ldap_dn="CN=Test User,OU=LDAP Dept Aggregate,OU=Departments,DC=example,DC=local",
+    )
+    fake_group = SimpleNamespace(member=[], save=MagicMock())
+
+    with patch.object(
+        DepartmentService,
+        "_ensure_department_group",
+        return_value="CN=DEP_LDAP Dept Aggregate,OU=LDAP Dept Aggregate,OU=Departments,DC=example,DC=local",
+    ), patch(
+        "employees.ldap.services.department_service.LdapOrganizationalUnitGroup.objects.get",
+        return_value=fake_group,
+    ):
+        DepartmentService()._reconcile_department_group(
+            dept,
+            "OU=LDAP Dept Aggregate,OU=Departments,DC=example,DC=local",
+        )
+
+    assert fake_group.member[0] == (
+        "CN=Test User,OU=LDAP Dept Aggregate,OU=Departments,DC=example,DC=local"
+    )
+    assert set(fake_group.member[1:]) == {role1.ldap_group_dn, role2.ldap_group_dn}
+    fake_group.save.assert_called_once()
diff --git a/backend/tests/manual/ldap_integration/test_entities_roundtrip.py b/backend/tests/manual/ldap_integration/test_entities_roundtrip.py
index f74c5dd5..d399e206 100644
--- a/backend/tests/manual/ldap_integration/test_entities_roundtrip.py
+++ b/backend/tests/manual/ldap_integration/test_entities_roundtrip.py
@@ -347,3 +347,51 @@ def test_department_role_service_roundtrip_syncs_live_ldap(
     service.delete_role(updated_role)
     assert not DepartmentRole.objects.filter(pk=updated_role.pk).exists()
     assert not LdapOrganizationalUnitGroup.objects.filter(dn=updated_role.ldap_group_dn).exists()
+
+
+def test_department_role_api_roundtrip_syncs_live_ldap_and_dep_group(
+    ensure_live_ldap,
+    superuser_client,
+    create_ldap_user,
+    ldap_cleanup,
+    unique_name,
+):
+    employee = create_ldap_user(first_name="ApiRole", last_name="Member")
+    department = _bootstrap_department_for_role_tests(unique_name("qa-role-api"))
+    ldap_cleanup(_department_dn(department))
+
+    create_role_response = superuser_client.post(
+        "/api/v1/department-roles/",
+        {"department": department.pk, "name": "Operator API"},
+        format="json",
+    )
+    assert create_role_response.status_code == 201, create_role_response.content
+
+    role = DepartmentRole.objects.get(pk=create_role_response.json()["id"])
+    ldap_cleanup(role.ldap_group_dn)
+
+    dept_group = LdapOrganizationalUnitGroup.objects.get(dn=department.ldap_group_dn)
+    dept_group_members = {_norm_dn(dn) for dn in list(dept_group.member or [])}
+    assert _norm_dn(role.ldap_group_dn) in dept_group_members
+
+    assign_response = superuser_client.post(
+        f"/api/v1/department-roles/{role.pk}/assign/",
+        {"employee_id": employee.pk},
+        format="json",
+    )
+    assert assign_response.status_code == 201, assign_response.content
+
+    role_group = LdapOrganizationalUnitGroup.objects.get(dn=role.ldap_group_dn)
+    role_member_dns = {_norm_dn(dn) for dn in list(role_group.member or [])}
+    assert _norm_dn(_employee_dn(employee)) in role_member_dns
+
+    revoke_response = superuser_client.post(
+        f"/api/v1/department-roles/{role.pk}/revoke/",
+        {"employee_id": employee.pk},
+        format="json",
+    )
+    assert revoke_response.status_code == 204, revoke_response.content
+
+    role_group = LdapOrganizationalUnitGroup.objects.get(dn=role.ldap_group_dn)
+    revoked_member_dns = {_norm_dn(dn) for dn in list(role_group.member or [])}
+    assert _norm_dn(_employee_dn(employee)) not in revoked_member_dns