Macbook Pro uses Wi-Fi from USB-connected iPhone Whenever I connect my iPhone to my Macbook Pro, it starts using the Wi-Fi from the phone, even though they're connected to the same one. When I disconnect the phone from the computer, the computer uses its own Wi-Fi connection.
This causes problems, e.g. if I'm downloading a large file to my computer with my phone connected and then I disconnect my phone, then the download fails and I'll have to resume it.
What could possibly be causing this? I use a VPN client on both my computer and my phone, but even when I disconnect from the VPN on both devices, the same behavior occurs.
You most likely have turned on your iPhones hotspot, which also works over USB.
On your iPhone open the settings app. Head over to personal hotspot. Turn it off and you should be good.
On the Mac side you should be able to check to which network you are connected to by opening the settings app and viewing the connected network under the network pane.