I've received a new iPhone 8 Plus and inserted a (previously used) Verizon sim into it. I hadn't restored from any backups. After a test call, the cellular->call time period showed about 2 minutes, which was the length of the test call. However, on the following day I've noticed the counter was up to 16 hours! I am pretty sure I haven't made any calls during the night, and nothing was running in the background (which is consistent with my Verizon account information, there is no unexpected activity in my usage statistics). Is this a bug? Has anyone seen that too? Does the sim-card somehow transfer the usage statistics after a certain timeout? (these 16 hours did not appear immediately). And, as I said, it was a clean install without any kind of transfers/migration.