after you sample offset profiles on a ground surface (say large). then when moving the design profile arnoud there is a large delay. what it's doing is probably regenerating the offset profiles. when taken away doesn't have the problem.
i don't see why this should be a problem since the offset profile has nothing to do with design profile.
2013 not sure 2012 definitely have the problem. but i doubt it will be fixed in 2013. just a rare thing probably only i use.
Civil 3D 2012 Work: Xeon W3503, 12GB, Quadro 2000, Dell P2211H x 2 Home: 3930k, 12GB, GTX 590, U3011, QX2710