First I tried disabling the iCloud and enable the iTunes backup, then it crashed again that night without any PANIC thingy on the diagnostics. After that scenario, I've immediately restored the phone and setup as a new iPhone without restoring the last backup. iCloud backup was disabled as well.
That step was my last option and I'm crossing my fingers that it would resolve the crazy issue. Fortunately, it's been 2 days without any hicups. Im still monitoring the phone every morning if it will shutdown agian. Hopefully not because I'm based in ME and it's difficult to return this unit to Apple US just to exchange.
I hope your phone is working fine now. Itunes backup is no biggie for as long as the phone is working. But im thinking that it's a software issue because it's only happening if iCloud back up is enabled. I hope it will get fixed on the next IOS update. Keep me posted dude! Thanks again!