Opcode shader compilation error when using a TextureSampleParameterCubeArray node with hardware ray tracing enabled

Materials containing a cube array texture sampling node will not compile when hardware ray tracing is enabled. The shader compilation error indicates that an invalid op code was used: "Opcode Sample not valid in shader model lib_6_6(closesthit)"

• Create a new project
• In the Content Drawer, create a Texture Cube Array
• In the Content Drawer, create a new material and open it
• Add a TextureSampleParameterCubeArray node and set the Material Expression Texture Base to the cube array texture
• Add a MakeFloat4 node and connect the output to the UVs input on the ParamCubeArray node
• Connect the ParamCubeArray's RGB output to the Base Color input of the main material node
• A shader compilation error will show up ("error: Opcode Sample not valid in shader model lib_6_6(closesthit).")
• Unchecking "Support Hardware Ray Tracing" and restarting the engine makes the compilation error disappear

[SM6] Shader debug info dumped to: “d:\p4\main\projects\ProjectName\UnrealEngine\ProjectName\Saved\ShaderDebugInfo\PCD3D_SM6\M_SpeedTunnel_Cubemap_Particle_492b22692a8dfd\Default\FLocalVertexFactory\TMaterialCHSFNoLightMapPolicyFAnyHitShader\0”
d:\p4\main\projects\ProjectName\UnrealEngine\Engine\Shaders\Private\RayTracing\RayTracingMaterialHitShaders.usf(0): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
error: validation errors
[SM6] d:\p4\main\projects\ProjectName\UnrealEngine\Engine\Binaries\Win64\RayTracingMaterialHitShaders.dxil(2816,9): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
RayTracingMaterialHitShaders.dxil:2816:9: error: Opcode Sample not valid in shader model lib_6_6(closesthit).
[SM6] d:\p4\main\projects\ProjectName\UnrealEngine\Engine\Shaders\Private\RayTracing\RayTracingMaterialHitShaders.usf(0): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
RayTracingMaterialHitShaders.dxil:5257: error: Entry function performs some operation that is incompatible with the shader stage or other entry properties. See other errors for details.
[SM6] d:\p4\main\projects\ProjectName\UnrealEngine\Engine\Shaders\Private\RayTracing\RayTracingMaterialHitShaders.usf(0): Shader TMaterialCHSFNoLightMapPolicyFAnyHitShader, Permutation 0, VF FLocalVertexFactory:
RayTracingMaterialHitShaders.dxil:5257: error: Function uses features incompatible with the shader stage (closesthit) of the entry function.