Summary
When using Custom Primitive Data to drive texture selection per asset, it updates within a live edit session, but not within the viewport.
I believe this is a Unreal Engine bug (Unreal Engine Issues and Bug Tracker (UE-306679)), but it is a problem in UEFN too by inheritance.
Please select what you are reporting on:
Unreal Editor for Fortnite
What Type of Bug are you experiencing?
Assets
Steps to Reproduce
Create a material using Custom Primitive Data to drive some visual aspect of the mesh.
Allocate it to a mesh, then place the mesh within a HISM Blueprint Component.
Drag out the HISM BP component, and attempt to alter the CPD value.
Expected Result
The material should update to match the CPD value.
Observed Result
You may get visual updates when sliding the values, but not when typing or after you have let go sliding the value around - it reverts back to as if CPD has no effect within the Viewport. Within a launched session it works as expected.
Platform(s)
UEFN, PC
Upload an image
Additional Notes
You can see in the screenshot above the difference between the two meshes. Top right is the live edit session showing the correct CPD values, on the left is the same values but the mesh is not updated.