diff --git a/app/finders/issues_finder.rb b/app/finders/issues_finder.rb
index b47e8a47a7fc06f2e4561151a285984d9d121a12..8e7bc5d49c39d572bcb97c425aa2ce3d4952cb31 100644
--- a/app/finders/issues_finder.rb
+++ b/app/finders/issues_finder.rb
@@ -118,7 +118,7 @@ def by_parent(items)
     namespaces = if relations.one?
                    relations.first
                  else
-                   Namespace.from_union(relations, remove_duplicates: false)
+                   Namespace.from_union(relations)
                  end
 
     items.in_namespaces(namespaces)