Is there any news of this issue? I haven't seen anything about it, and I have only seen this HUGE spike in data consumption since I upgraded from my Galaxy Nexus to the S4.
Before this I had to actually TRY to reach my 4GB limit, streaming netflix over the mobile network, downloading podcast episodes, etc. But for some reason now, when I am using Wifi both at work and here at home, I have, only over the last week or so, been getting the text warnings about my data consumption.
So far the only solution I am trying, which I am starting now, is to turn off the mobile data when I am at home or at work, but turning it on in between for GPS and music streaming (which I did before and it never caused the data to spike like this.
I am worried that I will unintentionally go over my limit, despite the care I take in using Wifi whenever possible.