Then you should be running 5.0.5, not 6b12.
I agree, If you want stability stick with 5.0.6
I have been on b13 since its release and after redoing my cache pool ( completely wiped the drives and started from scratch letting the GUI on b13 do its thing ) and i have had NO issues so far. I have 8 dockers running off the cache pool with no issues at all so far