HeliDriverNZ
We have Raven II with the same problem up here in the sunny north. Anything close to the forward C of G and the oscillation occurs - not just in descending turns - I've had it in a flat and slowish turn after turning off the runway at the end of an approach. No joy as yet from Robinson or their agents in NZ although the agents have recently flown the machine and have now experienced the problem (which they previously wouldn't believe existed) - scared the sh.t out of them