A week or two ago I realised that - seemingly after a recent SD update - my Airspace Wanings settings were all reset to OFF, with the exception of Parachute Dropzones (which was defaulted to ON although I as far as I remember I had this set to OFF). This is the place in Navigation Options where you select the airspace categories you want SD to alert you of. I observed this simultaneously on two iPads (iPad mini 5 and iPad Pro 2020). AFIK, the user settings here are NOT synchronised across devices. 

Most airspace warning options in SkyDemon default to ON, so there is no circumstance in which SkyDemon, through a corrupted settings file or otherwise, would reset those to OFF. Is there a chance anyone could have got hold of your device and gone through playing with the settings?