Yes, discussed quite a bit on the Gen 14 forums OTA section. Doesn't matter if you are connected to wifi or not, it will use the cellular connection. Similar to how your Fordpass app works and can start your truck (even nowhere near wifi) - it always has a cellular connection. Ford charges for features such as using it as a hotspot and now Alexa I hear, but it always has a connection to AT&T unless you rip your modem out. Pretty much speculation why they aren't utilizing wifi for OTA, but some think that's why updates roll out so slow to a select number of trucks at once.
I have never hooked up my truck to wifi and I have gotten regular updates.