Perhaps it's a component issue limited to a certain production run.
I *have* had one instance of Dolby Vision weirdness with my 9000, concerning the new Arrow 4K release of Dune. On the 4K disc there are about a half dozen "making of" video extras produced in 2005. If I have DV turned on I get...
I have the Panasonic DP-UB9000, and before that the Panasonic DP-UB820, and before THAT, the Oppo UDP-203. Played dozens of 4K titles on all three units and never had a single lockup.