Looks like the full factual NTSB report was released on the S97 "hard landing" back in 2017.
5 seconds of roll oscillations up to 60 degrees (!) followed by rotor intermeshing and destruction. Could have been a far worse outcome. The whole incident reminds of the control issues experienced on XH-59 back in the 70s causing the loss of the first airframe (intermeshing blades in that incident as well) with the 2nd getting airworthy 2 years later.
https://www.verticalmag.com/news/nts...ider-accident/
Actual report:
https://dms.ntsb.gov/public/62000-62...323/624201.pdf