diff --git a/libs/full/parcelport_mpi/include/hpx/parcelport_mpi/sender_connection.hpp b/libs/full/parcelport_mpi/include/hpx/parcelport_mpi/sender_connection.hpp
index 9eb969d3708..42cfb4419b3 100644
--- a/libs/full/parcelport_mpi/include/hpx/parcelport_mpi/sender_connection.hpp
+++ b/libs/full/parcelport_mpi/include/hpx/parcelport_mpi/sender_connection.hpp
@@ -201,7 +201,9 @@ namespace hpx::parcelset::policies::mpi {
                 request_ = util::mpi_environment::isend(
                     const_cast<void*>(
                         reinterpret_cast<const void*>(chunks.data())),
-                    chunks.size(), dst_, tag_);
+                    chunks.size() *
+                        sizeof(parcel_buffer_type::transmission_chunk_type),
+                    dst_, tag_);
                 request_ptr_ = &request_;
 
                 state_ = connection_state::sent_transmission_chunks;
diff --git a/libs/full/parcelset/tests/regressions/CMakeLists.txt b/libs/full/parcelset/tests/regressions/CMakeLists.txt
index b0a7ef5d7ea..7c48ce0967a 100644
--- a/libs/full/parcelset/tests/regressions/CMakeLists.txt
+++ b/libs/full/parcelset/tests/regressions/CMakeLists.txt
@@ -12,7 +12,9 @@
 
 if(HPX_WITH_NETWORKING)
   set(tests ${tests} very_big_parcel)
+  set(tests ${tests} very_big_tchunk)
   set(very_big_parcel_PARAMETERS LOCALITIES 2)
+  set(very_big_tchunk_PARAMETERS LOCALITIES 2)
 endif()
 
 foreach(test ${tests})
@@ -29,10 +31,13 @@ foreach(test ${tests})
     FOLDER "Tests/Regressions/Modules/Full/Parcelset"
   )
 
-  # Disable the test due to limited CircleCI resources
-
-  # add_hpx_regression_test( "modules.parcelset" ${test} ${${test}_PARAMETERS}
-  # TIMEOUT 900 )
+  # Disable the test for very_big_parcel due to limited CircleCI resources
+  if(${test} STREQUAL "very_big_parcel")
+    continue()
+  endif()
+  add_hpx_regression_test(
+    "modules.parcelset" ${test} ${${test}_PARAMETERS} TIMEOUT 900
+  )
 
 endforeach()
 
diff --git a/libs/full/parcelset/tests/regressions/very_big_tchunk.cpp b/libs/full/parcelset/tests/regressions/very_big_tchunk.cpp
new file mode 100644
index 00000000000..2bb93d4f379
--- /dev/null
+++ b/libs/full/parcelset/tests/regressions/very_big_tchunk.cpp
@@ -0,0 +1,100 @@
+//  Copyright (c) 2025 Jiakun Yan
+//  Copyright (c) 2025 Marco Diers
+//
+//  SPDX-License-Identifier: BSL-1.0
+//  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)
+
+#include <hpx/future.hpp>
+#include <hpx/hpx.hpp>
+#include <hpx/hpx_init.hpp>
+#include <hpx/runtime_distributed/find_all_localities.hpp>
+
+class Data
+{
+public:
+    Data() = default;
+
+    Data(std::size_t size)
+    {
+        for (auto i(0ul); i < size; ++i)
+        {
+            _data.emplace(std::make_tuple(i), std::vector<float>(3001));
+        }
+    }
+
+    auto size() const
+    {
+        return _data.size();
+    }
+
+    template <typename Archive>
+    friend auto serialize(Archive& archive, Data& object, unsigned int)
+    {
+        archive& object._data;
+        return;
+    }
+
+private:
+    std::map<std::tuple<std::size_t>, std::vector<float>> _data{};
+};
+
+class Component : public hpx::components::component_base<Component>
+{
+public:
+    Component() = default;
+
+    auto call(Data data) -> void
+    {
+        std::cout << "Data size: " << data.size() << '\n';
+        return;
+    }
+
+    HPX_DEFINE_COMPONENT_ACTION(Component, call)
+};
+
+HPX_REGISTER_COMPONENT(hpx::components::component<Component>, Component);
+HPX_REGISTER_ACTION(Component::call_action)
+
+class ComponentClient
+  : public hpx::components::client_base<ComponentClient, Component>
+{
+    using BaseType = hpx::components::client_base<ComponentClient, Component>;
+
+public:
+    template <typename... Arguments>
+    ComponentClient(Arguments... arguments)
+      : BaseType(std::move(arguments)...)
+    {
+    }
+
+    template <typename... Arguments>
+    auto call(Arguments... arguments)
+    {
+        return hpx::async<Component::call_action>(
+            this->get_id(), std::move(arguments)...);
+    }
+};
+
+int hpx_main()
+{
+    std::vector<ComponentClient> clients;
+    auto localities(hpx::find_all_localities());
+    std::transform(std::begin(localities), std::end(localities),
+        std::back_inserter(clients),
+        [](auto& loc) { return hpx::new_<ComponentClient>(loc); });
+    Data data(1444);
+    std::vector<decltype(clients.front().call(data))> calls;
+    for (auto& client : clients)
+    {
+        calls.emplace_back(client.call(data));
+    }
+    hpx::wait_all(calls);
+
+    return hpx::finalize();
+}
+
+int main(int argc, char* argv[])
+{
+    return hpx::init(argc, argv);
+}