Using WiFi even if it is disabled

My Edge 830 knows parameters of my WiFi network. However, under Edge's WiFi menu I have WiFi set to OFF and Auto Upload set to ON. 

I sometimes notice that my Edge 830 apparently somehow uploads ride data when my phone is very far from the bicycle (way outside of BT range). I suspect that it uses WiFi instead of BT to upload data, even though WiFi is set to OFF. 

Is that true? Does it mean that under the above settings Edge 830 can occasionally temporarily turn on WiFi on its own accord to upload the data?