I just upgraded from 5.6.3 to 6.7 rc1 yesterday afternoon. It initially locked after about 4 hours, no ssh or browser access, and required a hard reset. I then ran TS mode from the FCP plugin, left the dashboard window open on my screen, and went to bed. When i woke up this morning it had locked up again around 12.5 hours in. I am not running any VM's, this is purely a media server with minimal dockers. The logs are attached below.