There is a bug in the Shader Property name for _Reflect_Emission in the following Reflect Shader:
com.unity.reflect@3.1.0-preview.9/Runtime/Player/Shaders/Standard/StandardTransparent.shader
On line 50, the Emission property name is:
_Emission
However, it is referenced by the Inspector Panel GUI editor and other areas of the codebase as:
_Reflect_Emission
This would also make the shader property consistent with the StandardOpaque.shader.
Can you please make this minor change to fix the built-in RP support for Standard shaders.