diff --git a/single_include/flux.hpp b/single_include/flux.hpp
index 2932b01a..5413274b 100644
--- a/single_include/flux.hpp
+++ b/single_include/flux.hpp
@@ -8652,7 +8652,7 @@ struct set_union_adaptor
                      bounded_sequence<Base1> && bounded_sequence<Base2>
         static constexpr auto last(Self& self) -> cursor_type
         {
-            return cursor_type{flux::last(self.base1_), flux::last(self.base2_)};
+            return cursor_type{flux::last(self.base1_), flux::last(self.base2_), cursor_type::second};
         }
 
         template <typename Self>
@@ -9085,6 +9085,7 @@ inline constexpr auto set_intersection = detail::set_intersection_fn{};
 #endif // namespace FLUX_OP_SET_ADAPTORS_HPP_INCLUDED
 
 
+
 // Copyright (c) 2023 Tristan Brindle (tcbrindle at gmail dot com)
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)