Geometric path descents only work now and then. My solution in your case is; after you reach FL300 at the first waypoint, delete that restriction and enter FL300 as new CRZ alt with whatever speed you like. That'll give you a new T/D with idle descent after that.
In RYR we've reverted back to the 10.7 FMC update now, because of all the bugs on the 10.8, which also includes this geo. path rubbish.