Since updating to 1.2.0.beta6 my site has crashed twice and needed to be rebuilt twice to fix it in a 3 day period.
Tested from multiple systems and users using Mac (Safari), Windows 8.1 (FireFox, Chrome, IE), Android Lollipop (Chrome, FireFox), iOS 8 (Safari)
Rebuilding seems to fix it, but it crashes again after about 24-30 hours. I am running default discourse, no plugins, the specs of my server are 4 times the recommended settings, no massive traffic spike or issues on the server, using the docker install, only have a couple hundred users and 10k posts (avg 800-900/day), site is 20 or so days old.