GX450 Factory Reset

When I perform a factory reset on the GX450, even when select “reset all,” certain settings, such as wireless network, are retained. Has anyone else experienced this and is there a workaround? When I factory reset and don’t wish to preserve core settings, shouldn’t this remove everything? I’m using the most current firmware version

Power off, then remove the SIM card, then reset, power off, then put it back in.