When summoning my vehicle, it has a disturbing tendency to do the weirdest Roach-like shit.

I've had it summon on top of a building.
I've had it summon upside down.
I've summoned it and subsequently been ran over by it.
I've had it summon underwater.
I've had it summon on the other side of an impassable wall.
I've had it summon on top of or even inside of other vehicles.

Come on CDPR, fess up; you used the Relic on Roach and then transplanted her consciousness in to the player's vehicles, dintcha?

Cool xD Honestly I mostly use bikes and they spawn like 50m afar and auto-drive to me. I have not see any spawn bug, but they are pretty funny. What I have seen are cars suddenly explode, or random cars flying by a weird collision.

Bike can also ride you over if you get in its way before it stops. Would not call it a bug though.

Jackie's bike has amazing brakes. When it came to me it braked so hard it almost flipped over.

Yeah, Hotel Mission to install Malware...

Called my vehicle on the way up in the elevator, Jackies Bike was waiting in the office next to the computer
so in true Matrix fashion, I rode it out of the window from the top of the Hotel completing the mission.