(This is a strange thing that happened a couple of weeks ago.)
A friend of mine just recently destroyed his last mobile device, so I decided to give them an old phone I no longer use (which is an unlocked Verizon S8). Prior to this Samsung device, their last ~6 phones have been various brands that weren't Samsung (such as Motorola and Apple).
Moving on, we performed a factory reset on the S8 phone to wipe the saved data out, and when my friend finally got past the initial, basic phone set up, they started altering some of the categories on the Settings app. He decided to turn Wi-Fi Calling on, and when he was prompted to put in his E911 address, he saw that his specific address had been automatically filled in.
The strange part was that the device could not have known their address, for sure, because they never saved their home address on any autofill services — not using Samsung Pass (which is Samsung Wallet, now) or in their Google Password Manager.
