I also believe WiFi Assist is possibly causing the problem. I recently started having this same issue.
Here's how it goes for me:
- I disable WiFi in Settings--> WiFi
- I disable Hotspot in Settings--> Hotspot
- While Settings is open, usually within a minute, I watch them turn back on.
As LiveOnTheEdge suggested, I turned off WiFi Assist. The behavior stopped.
Here's what I think is going on (it's just an educated guess):
WiFi Assist monitors both your WiFi and Cellular connections. If your WiFi signal is weak, it will attempt to switch over to cellular.
My current situation is this:
My power has been out for 2 days because of a snow storm, so I have no WiFi. On top of that, the cellular signal is always poor. My suspicion is that WiFi Assist also works the other way. And when my devices think the cellular signal is to poor it turns on WiFi to try that option.
That conjecture could be totally wrong, however, turning off WiFi Assist in:
- Settings--> Cellular Data
- Scroll to the bottom of that page
- Disable (Turn Off) WiFi Assist
The problem has gone away.
When all of the possible, and even the improbable possibilities have been rule out, the impossible must be questioned.