UI Material block causes lag spikes when loaded into a UI

Summary

In the latest update (36.20), loading a material block UI with a linked value (e.g, Progress:= 1.0) causes a lag spike lasting several seconds. This issue is particularly problematic on lower-performing consoles.

Please select what you are reporting on:

Unreal Editor for Fortnite

What Type of Bug are you experiencing?

Verse

Steps to Reproduce

Create a Verse script that displays a UI to the player.
In the UI, include a Material Block widget.
Set a material parameter (e.g., Progress := 0.5) linked to the material block.
Link the opening UI to a mutator zone or a button

Expected Result

The UI you should with no lag spikes/freezes

Observed Result

Run the script and observe the lag spike when the UI is shown.

Platform(s)

PC

FORT-943376 has been added to our ‘To Do’ list. Someone’s been assigned this task.