I had parasitic draw from a 12v phone adapter that wasn’t powering down when the car was locked, took me forever to realize that cheap Amazon gadget was causing issues!
My issue is related to a 12v charger as well, except a little different. Sometimes the car won’t start (engine doesn’t even turn) _until_ I unplug the 12v charger. Then it starts right away. No idea why, but would love an explanation from someone knowledgeable!