I agree with Sentinal this is an association issue. If some of your Bryce materials work I would take a close look at why and see what is the difference between the ones that work and the ones that do not. Loading them in your user file may be a better way to go according to the Manuel however I have done both with no problems. Also if you can upload one of the materials that do not work and someone can take a closer look at it perhaps. I notice you are using Vue4, downloading the update to Vue4.12 maybe very helpful here and in many other areas of your program.