Default Battery Drain during idle time

This problem only appeared for me when I upgraded to 4.4.3. 4.4.4 didn;t solve it too. I'm on stock ROM, rooted.

Basically instead of draining 2-3% over 8 hours of sleep time at overnight, it would drain about 16%. There are no wakelocks, and the battery monitor on Android doesn't reveal much... maybe Android System is draining more than usual but I can't be sure, and everything else looks normal. I really can't pinpoint the root of this.

What I do know is this - if I reboot the phone the problems goes away, for one or two days. And then for no apparent reason the phantom drain comes back. Only solution to it is to reboot every now and then. Very annoying. Anyone else has encountered this?