diff --git a/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.cpp b/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.cpp
index b02d73630..646f72e44 100644
--- a/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.cpp
+++ b/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.cpp
@@ -448,6 +448,7 @@ void RTAO::CreateSamplesRNG()
         m_samplesGPUBuffer[i].value = XMFLOAT2(p.x * 0.5f + 0.5f, p.y * 0.5f + 0.5f);
         m_hemisphereSamplesGPUBuffer[i].value = p;
     }
+    m_numAOSamplesUploadFrames = m_deviceResources->GetBackBufferCount();
 }
 
 void RTAO::GetRayGenParameters(bool* isCheckerboardSamplingEnabled, bool* checkerboardLoadEvenPixels)
@@ -547,8 +548,11 @@ void RTAO::Run(
     }
 
     // Copy dynamic buffers to GPU.
+    UpdateConstantBuffer(frameIndex);
+
+    if (m_numAOSamplesUploadFrames)
     {
-        UpdateConstantBuffer(frameIndex);
+        m_numAOSamplesUploadFrames--;
         m_hemisphereSamplesGPUBuffer.CopyStagingToGpu(frameIndex);
     }
 
diff --git a/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.h b/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.h
index 7bc67fba0..0e17cc347 100644
--- a/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.h
+++ b/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/RTAO/RTAO.h
@@ -108,6 +108,7 @@ class RTAO
     StructuredBuffer<AlignedHemisphereSample3D> m_hemisphereSamplesGPUBuffer;
     BOOL m_isRecreateAOSamplesRequested = true;
 
+    UINT            m_numAOSamplesUploadFrames = 0;
     UINT		    m_numAORayGeometryHits;
     bool            m_checkerboardGenerateRaysForEvenPixels = false;
 
diff --git a/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/SampleCore/Shaders/util/GenerateGrassStrawsCS.hlsl b/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/SampleCore/Shaders/util/GenerateGrassStrawsCS.hlsl
index 911bd15b6..9af105f63 100644
--- a/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/SampleCore/Shaders/util/GenerateGrassStrawsCS.hlsl
+++ b/Samples/Desktop/D3D12Raytracing/src/D3D12RaytracingRealTimeDenoisedAmbientOcclusion/SampleCore/Shaders/util/GenerateGrassStrawsCS.hlsl
@@ -194,6 +194,9 @@ void main(uint2 DTid : SV_DispatchThreadID)
     {
         VertexPositionNormalTextureTangent vertex;
         vertex.position = 0;
+        vertex.normal = 0;
+        vertex.textureCoordinate = 0;
+        vertex.tangent = 0;
         uint threadID = DTid.x + DTid.y * cb.p.maxPatchDim.x;
         uint baseVertexID = threadID * N_GRASS_VERTICES;