<Warning, not thread related> Had my first macOS Sierra glitch this morning. Opened Notes and it promptly crashed:
Crashed Thread: 9 Dispatch queue: NSManagedObjectContext 0x6180001ca8c0
And did the same thing the second time, and the third after a restart.
Internet to the rescue, turn off iCloud sync for Notes, open Notes (didn't crash now), turn on iCloud sync again and everything seems to be functioning again.