I lost at least an hour of work on my Realm yet again.  Work that is not easy to replicate.  I logged off as normal, came back after an hour or so and everything had reverted to the start of my last session.  I lost 5 mob heads gained through charged creeper explosions, and a lot of grindy work besides that.  If this isn't addressed seriously I'm going to cancel my Realm, this is a remarkably frustrating experience to CONTINUE to encounter with no communication about why it is happening.