Rather than edit my post above, I may have spoken too soon. I'm experiencing a problem which may be related to wrist detection. My watch is locking several times a day while it's still on my wrist, so I need to enter my passcode or unlock with my phone. I tightened the strap and cleaned the back of the watch to eliminate those as possible causes, but it's still doing it. I had this issue only rarely on prior versions of the OS, but it's happening frequently since I installed 6.0.