Google and Netflix are both aware of the matter. The former's Don Merrill says that the problem is that the Netflix app is freezing your phone or tablet while it is locked which makes it look as though your phone has been turned off. Merrill suggests that until a fix is sent out, those with a Nexus device running Android 4.3 either refrain from updating to the new build (unless you just bought the new Nexus 7, of course) or uninstall the Netflix app until the bug is killed dead. He also says that Google has its top men working on a solution, so don't let this keep you up all night!
The actual issue is that the Netflix app causes your phone to freeze while locked, giving it the appearance of being powered off.
So, if you use the Netflix app on your Nexus 4 (and especially if you have a Chromecast!) either stick to 4.2.2 or uninstall the Netflix app until the issue is fixed."-Don Merrill, Google
source: Reddit via Ubergizmo