I have families with instance parameters that change stuff in the project which have all other versions but in 2018.1 they will often not work. I created a video that shows what happens. https://www.screencast.com/t/XCsrlGwERKO9
I can check the box or change the numerical value and the "apply" button will become active until I try to select it. then it grays out and the change that I made reverts to what it had been.
Sometimes if I go to a different view or reopen the project or sync then it will work as it should.