I parked my ATV outside the garage at the bottom of the ramp so it could get sun to recharge and it disappeared. I tried locating it with the command and I reached the edge fence of the map before seeing any sign of it. I also tried the reset vehicle option in the save menu but it did nothing as far as I can tell, compass indicator for vehicle still points off into the distance beyond the border fence.
Viewing post in Voices of the Void 0.8.0 Bug Reports
Update: found it!
Not sure how but I think the Ariral ATV refill event was bugged because I used the hook to climb the border fence and found it with about 300 gas and -700 HP near the invisible map border, it was a bitch to get back over the fence but I did manage and got it repaired.
Still no idea why the save menu reset vehicle option didn't work but I got my ATV back so I'm not super concerned.