One reason your example is not showing snaps in prior versions is that the 3D objects aren't producing any snaps. I believe there may have been some improvements in nurbs snapping in this version. Or, perhaps 3D edge snaps are typically turned off in prior versions. Anyway, I can observe unwanted 3D snaps in prior versions with a test case involving a 3D symbol contained within a hybrid symbol, so yes it really is a legacy bug.
Another reason snapping bugs have lurked below the surface in prior versions is that they went unnoticed. With the sweet snap hilighting in VW2009, many snap problems came to the surface, and we fixed them. This one snuck by, obviously.