If you found so many reports of this issue but not a single solution, then that should tell you something. Namely, it should tell you a universal guide to fix this kind of issue simply does not exist, and it never will. Random reboots are just that - random, unpredicatable, quite hard to explain or trace, especially from afar. That is why I said the key is probably in your own logs, if even there. The best people here can tell you is "try this" or "try that" and hopefully you'll stumble upon something that will fix it. Don't hope for more than that.