The camera boots in Normal mode, so will start a Normal recording. During whatever duration you have set it'll determine it's actually parked, and switch to Parking mode. That's why you get a Normal recording on your reboot.
Some people set the motion sensitivity to zero, and crank up the G-sensors to full. That'll cause an Event recording when your car is smacked, but you'll miss gentle touches/scratches and all movement.
The rest of us grit our teeth, leave motion sensitivity at 1, and understand that will mean lots of extraneous parking files (windy, birds or larger insects, people, etc). Of course, if you have anything smaller than a 64Gig card, you won't like that option much.
Brad.