diff --git a/core/test/TestCustomModelsFromONNXForAlpakaCuda.cxx b/core/test/TestCustomModelsFromONNXForAlpakaCuda.cxx
index 5ad9383..df49e49 100644
--- a/core/test/TestCustomModelsFromONNXForAlpakaCuda.cxx
+++ b/core/test/TestCustomModelsFromONNXForAlpakaCuda.cxx
@@ -155,6 +155,9 @@
 #include "ConvWithAutopadSameLower_FromONNX_GPU_ALPAKA.hxx"
 #include "input_models/references/ConvWithAutopadSameLower.ref.hxx"
 
+#include "ConvWithAutopadSameUpper_FromONNX_GPU_ALPAKA.hxx"
+#include "input_models/references/ConvWithAutopadSameUpper.ref.hxx"
+
 #include "ConvWithStridesPadding_FromONNX_GPU_ALPAKA.hxx"
 #include "input_models/references/ConvWithStridesPadding.ref.hxx"
 
@@ -2328,6 +2331,43 @@ TEST_F(SofieAlpakaTest, ConvWithAutopadSameLower)
 }
 
 
+// SAME_UPPER with odd total padding (x[1,1,4,4], k3, s2): the extra pad goes at the end,
+// so the output differs from SAME_LOWER. Guards the SAME_UPPER pad split (issue #33).
+TEST_F(SofieAlpakaTest, ConvWithAutopadSameUpper)
+{
+   constexpr float TOLERANCE = DEFAULT_TOLERANCE;
+
+   std::vector<float> input(16);
+   std::iota(input.begin(), input.end(), 0.0f);
+   auto input_h = alpaka::allocBuf<float, Idx>(host, Ext1D::all(Idx{input.size()}));
+   float* input_ptr = reinterpret_cast<float*>(alpaka::getPtrNative(input_h));
+   for (Idx i = 0; i < input.size(); ++i) input_ptr[i] = input[i];
+
+   auto input_d = alpaka::allocBuf<float, Idx>(device, Ext1D::all(Idx{input.size()}));
+   alpaka::memcpy(queue, input_d, input_h);
+   alpaka::wait(queue);
+
+   auto result_h = alpaka::allocBuf<float, Idx>(host, Ext1D::all(Idx{sizeof(ConvWithAutopadSameUpper_ExpectedOutput::all_ones) / sizeof(float)}));
+
+   {
+        SOFIE_ConvWithAutopadSameUpper::Session<alpaka::TagGpuCudaRt> session("ConvWithAutopadSameUpper_FromONNX_GPU_ALPAKA.dat");
+        auto result = session.infer(input_d);
+        alpaka::wait(queue);
+        cudaDeviceSynchronize();
+        alpaka::memcpy(queue, result_h, result);
+        alpaka::wait(queue);
+   }
+
+   float* res_ptr = reinterpret_cast<float*>(alpaka::getPtrNative(result_h));
+   float *correct = ConvWithAutopadSameUpper_ExpectedOutput::all_ones;
+   constexpr size_t nOut_sameUpper = sizeof(ConvWithAutopadSameUpper_ExpectedOutput::all_ones) / sizeof(float);
+
+   for (size_t i = 0; i < nOut_sameUpper; ++i) {
+      EXPECT_LE(std::abs(res_ptr[i] - correct[i]), TOLERANCE) << "i=" << i;
+   }
+}
+
+
 TEST_F(SofieAlpakaTest, ConvWithStridesPadding)
 {
    constexpr float TOLERANCE = DEFAULT_TOLERANCE;
diff --git a/core/test/input_models/ConvWithAutopadSameUpper.onnx b/core/test/input_models/ConvWithAutopadSameUpper.onnx
new file mode 100644
index 0000000..bf0a5c8
Binary files /dev/null and b/core/test/input_models/ConvWithAutopadSameUpper.onnx differ
diff --git a/core/test/input_models/references/ConvWithAutopadSameUpper.ref.hxx b/core/test/input_models/references/ConvWithAutopadSameUpper.ref.hxx
new file mode 100644
index 0000000..60844c7
--- /dev/null
+++ b/core/test/input_models/references/ConvWithAutopadSameUpper.ref.hxx
@@ -0,0 +1,3 @@
+namespace ConvWithAutopadSameUpper_ExpectedOutput {
+float all_ones[] = {45.0, 39.0, 66.0, 50.0};
+} // namespace ConvWithAutopadSameUpper_ExpectedOutput