This is caused by FLightmassMaterialProxy doesn't have GetStaticParameterSet() function. (FMaterial::GetStaticParameterSet() is called.)
It can be fixed by adding the following function to FLightmassMaterialProxy.
I shelved this code into CL# 14090262.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-96749 in the post.