Very strange. I'm guessing it's some sort of system app misbehaving, but no clue why or what it's for.
Have you tried clearing the phone's cache partition?
On the S7:
Turn the phone off.
Press & hold the Power, Volume Up, & Home buttons at the same time. Hold them until you get a black screen with tiny blue writing saying "Booting recovery" or similar.
Let go when you see that screen.
It may say it's installing a system update. Just wait through this.
When you get to a "weird" text menu on a black background, use the volume down key to highlight "clear cache partition" (or similar)
Once it's highlighted, press the power button to select it. If it asks for confirmation, tell it yes.
Once compete, the list will show up again. Select the Reboot option (Not boot to recovery).
If that doesn't seem to work, you might want to use the quick toggle in the notification pull down to turn mobile data off when you're not using it.
Might also be worth it to contact your carrier & see what they have to say.
Sent from my Moto Z