Material Parameter Collection Node in Material Function Resets to First Item

Steps to reproduce:

  1. Make Material Function
  2. Make Material Collection Parameter with some Vector4 parameters

  1. Reference the Materical Collection Parameter in the Material Function, choosing several different items


  1. Save the Material Function
  2. Re-open the Material Function
  3. The Material Collection Parameters have all reset to the first one in the Material Collection Parameters list


E: I am seeing this in the regular Material too, when tested. Is the Material Parameter Collection node just broken in 4.11.2?

Upon further investigation, it looks like this is somewhat fixed, but not clearly stated in 4.12.

“MaterialParameterCollection will correctly rename entries when duplicate named items are added.”

So if you are pre 4.12 and you use “Duplicate Item” to create new entries, the reference is never updated and it just breaks permanently.