[lucasar]

Maybe the culprit is the technology and nasty tricks backing the "Find my device" feature? iOS devices will share their location (and potentially other data) with other nearby devices using a mesh network with certain frequency, even in Airplane mode. Also if the iPhone/iPad is powered off using the "power off" feature, the device will still be findable.

This capability is one of the strong selling points for consumers. The modern, average thief will often toss away these devices and settle with the rest of the loot because of this.

Sounds like OP wasn't aware of this.

[TakeFlight007]

I'm aware of "Find My Device" that's a documented feature. Find My beacons go OUT (your device tells others where it is). This is 84MB coming IN. Different thing.

[lucasar]

Well, such traffic goes OUT somewhere and that somewhere is other iDevices so that's traffic coming IN for them, no? I don't have evidence supporting either possibility other than the fact that there's indeed an obscure mesh network involved for "Find My" to operate. I hope this is the starting point to figuring out what their infrastructure does.