We would like to change some of their parameter names, however when renaming a parameter, its value in all of the corresponding material instances resets to the base material default value.
This is a regression. This does not occur in 4.17. This does not occur if the base material does not include a material function.
Result: Mat_Test2_Inst the Vector Parameter Value for 'BaseColor123' has reset to default value of base material.
Expected: Changing parameter name doesn't change parameter values.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-52729 in the post.