I'm experiencing the same problem (in SU Pro 7.1). The Options Window workaround has no effect whatsoever. A few changes stick (e.g, inversion of a bumpmap bitmap), most are lost, no matter if I open and close the options window and save and reload the model. Changes that get lost seem to be lost the very moment I hit Apply - the material preview doesn't change, and if I reopen the panel that I just closed values will already have reverted back to their initial state.

This is a pretty serious and seriously galling bug to find in software with this pricetag!