diff --git a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMesh.cpp b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMesh.cpp
index 2c8f210b2..c4c9d094d 100644
--- a/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMesh.cpp
+++ b/src/graphics/shader/recompiler/backend/spirv/spirvEmitterMesh.cpp
@@ -187,7 +187,7 @@ void EmitMeshEntryPoint(EmitterState& state) {
 				vertex[component] = state.builder.AllocateId();
 				state.builder.AddFunction(
 				    spv::OpBitFieldUExtract, TypeU32(state), vertex[component], packed,
-				    ConstantU32(state, component * 10u), ConstantU32(state, 10));
+				    ConstantU32(state, component * 10u), ConstantU32(state, 9));
 			}
 			const auto triangle = state.builder.AllocateId();
 			state.builder.AddFunction(spv::OpCompositeConstruct, TypeU32Vector(state, 3), triangle,
diff --git a/tests/shaderCfgTests.cpp b/tests/shaderCfgTests.cpp
index 8519eaec0..3d155c8c1 100644
--- a/tests/shaderCfgTests.cpp
+++ b/tests/shaderCfgTests.cpp
@@ -11160,6 +11160,8 @@ void TestMeshExportStorage() {
               !SpirvSourceHasInstructionUsing(source, "OpAccessChain",
                                               "vsharp %uint_0 %uint_4294967295"),
           "mesh draw prefix was lost or spilled shader data wrapped into push constants");
+    Check(SpirvSourceHasInstructionUsing(source, "OpBitFieldUExtract", "%uint_10 %uint_9"),
+          "NGG primitive vertex indices must be 9 bits; bit 9 of each field is the edge flag");
     const auto &binary = result.spirv;
     for (const auto builtin : {3u, 4u}) {
       auto expected = builtin == 3u ? std::vector<uint32_t>{0, 3}