tinfoilhatguy,
Set up and account on here to say thanks. I'm not saying it's the "right" way to fix it, but as it seems I still have full functionality without it, I too disabled the NetworkSystemProvided service and...Ta Da!...no more pop ups. My hope is that Sprint figures out what went wrong since it happened to quite a few people over the last 72 hours, but for now, this will suffice.
For what it's worth, I'm using a rooted Note 4 with stock rom and TWRP recovery. Nothing to fancy. I tried rebooting, wiping cache and dalvik cache, uninstalling SprintZone update, restoring a previous NAND backup, factory reseting, and a full OS wipe with a NAND restore all to no avail. I also do not have Facebook Messenger installed so that wasn't going to work for me either. Anyways, just wanted to say "Thanks for the suggestion". Back up and running now.