Hey ,
in one of my applications I had a similar problem. I was changing light colors of ambient lights using umg, unfortunately the reflections of the light color wouldn’t update.
However, I used the workaround mentioned by DanielW: I created a “execute console command” node and put in the command ‘r.ReflectionCapture’. It is triggered everytime the user applies the changed material. the user will see a loading screen for about .2 sec while the reflection captures are updating.
Not ideal, but working.
Another thing that comes to my mind ist experimenting with planar reflections. maybe this’ll work better for you. planar reflections are updated constantly.