With the fall weather, we leave the windows open.
I have ‘Return to Clean Air’ toggled off yet when we come home the air purifier is running.
Also, I get a message on my phone stating we will come home to clean air.
For now, I just unplug it when we leave and have the windows open.
I have removed and reinstalled the purifier with the same results.
If you have the air purifier running and set to auto if the AQI reaches certain levels the motor will speed up, I know the first jump is at AQI of 50. The only way to avoid that is to set the air purifier to a desired speed or turn it off.
The message you are getting is it a notification or in the app itself?
Exactly. It is turned off in the app but it really isn’t.
Update
Seems to have fixed itself. Works as designed. 
Let’s blame it on sunspots.
Operator error/loose nut behind the wheel.
The air purifier was turned off at the purifier, but not in the app. Once I turned it off in the app, no more notifications and the purifier stays off.