When disabling WWAN from quick settings, or from mobile network settings top right toggle the modem at times is lost and and modem as well as UI behavior is inconsistent or unreliable. 

1. turn off mobile network -> observe phone switches to airplane mode -> also observe sometimes (probably when wifi is enabled) it goes to No WWAN Adapter Found screen

2. select turn off airplane mode button in mobile network settings -> observe nothing happens -> if the No WWAN Adapter Found screen shows the toggle works

3. repeat the same between quick setting and mobile network settings

4. additionally once the WWAN adapter is back up and running it lost its toggle preference settings for mobile data, data roaming and reverts to off -> should be restored to prior settings, whatever they were

Use requires both approaches to get the modem back up and running.