Adding a piece of information to Microsoft people (hoping they can reply with a solution).
Event viewer always shows the same list of errors and warnings before the incident:
First Error BTHUSB Event ID 17,
then 4 DeviceSetupManager Warnings (Event ID 202/200/202/201),
then Warning BTHUSB Event ID 34
and finally Error DistributedCOM Event ID 10016.
This sequence never changes and always occurs before hibernation.
If only one or two of these warnings or errors occur (e.g. Error DistributedCOM Event ID 10016 alone or even repeated several times), no problem, but when the above sequence completes, bang, hibernation.
I have had a very similar experience to MassimoSNZ above. My new Surface Pro shut down twice in the space of 20 minutes, and showed the same two errors in the event viewer both times (Event 17, BTUSB, followed by Event 10016, Distributed COM). I was browsing
the internet at the time (using Chrome), on battery power (55% battery), with only a Type Cover attached.