You have learned a good lesson: the idealized part is associated to the master part, then any geometric change in the master model will affect finally the FEA model, as desired!.
I suggest to make actions like washer imprints in the idealized part, not in the FEM part, this way your mesh will update correctly. Is true that the idea with NX developpers is to create "geom recipes" for everything like circular imprints, stitch edges, etc.. to perform in the FEM environment, then the mesh will update correctly in case of editing the master model, this is new in NX8, good job!!.
Also, when dealing with RBE2/RBE3 elements, my suggestion is to define the mesh based in the geometry always, not in the mesh. For instance, instead to use "node-to-node" to define an spider, use better "point-to-edge", this way if you update the hole diameter the mesh will update correctly. Etc...