On my Nexus 5 I had aokp installed and the indicator was part of the rom and after settings things up and disabling all auto update in apps I had (for the most time) zero network activity.
Now on my bacon I have the same apps, with the same setup (even uninstalled a couple apps) but the newtork activity just won't stop.
I just downloaded the "Network Connections" app and it seems that "Google Contacts Sync" uses the network all the time.
I already tried turning off all sync functions, but it just won't stop.
I mean it's only a couple of bytes most of the time... but shouldn't it be dead silent, when sync is turned off?