Yes this happened to me too. I’ve been trying out the new layered material since the first preview. It works fine before preview 5, All the instanced layered material now will crashes when ever i click the layer parameter tab.
There is also a strange behavior with just using a regular material instance (non layered), the parameter just won’t change. First I thought the real time was unchecked, but that was not the case and when i hit save the material parameter instance sometimes disappear but there was no changes were made. The regular material behaves normal again after i disable the layered material in experimental. Can some one confirm to check on this?