I got the same issue here…
iPhone 14 Pro with iOS 17.1.2
I am currently trveling in France and my SIM card just didn’t work over here so I bought a local SIM card with a cap of 50GB. Me and my friend are sharing the network and I’m sharing via hotspot.
I’ve noticed the problem early into our trip and they only have used 931MB. I have used about 1.9GB. and we are 5 days into our trip.
This morning, other device was using about 29GB. and since the last half hour, we have been sitting in the train. In that time. The Other devices has gone up to 38.4GB.
My hotspot is off, my wifi and bluetooth is off and I’ve shut down all of my personal devices.
I’ve read that someone called their network provider and they actually used up only 2GB or so and they had a visual bug. But someone else’s provider said that they actually used up the amount that was told in the phone. I’m quite scared since we are on a very tight budget and I don’t want to pay more for that.
If it’s an apple issue, I hope they fix it because I’ve been seeing more and more post about this but they haven’t said anything as usual…