GTAV - People keep stealing MY cars!! AKA disappearing car bug

Ironic to be complaining about cars going missing in a game about stealing cars I know but, this glitch saddens me so much. I love the car modding aspect of GTAV but it's pretty useless if everything I get my grubby little mitts on goes walkabout shortly after. But it's been fixed in v1.1!! I hear you say. Not for me it hasn't, played a couple of hours after the title update (the first one, there was another last night but I believe this was online fixes only) and several cars went missing from garages (the large, non safe house ones).

I'm not entirely sure when the game considers a car 'owned' so it respawns back at the impound if lost. Driven for a long time? Modified? Garaged at some point? Or just anything I have set foot in. I modified an Audi RS4-a-like fully, got wasted, opened the doors to the impound only to find a green Jeep waiting for me. I've never driven a green Jeep. I sure as hell wouldn't have left a Beyonce CD playing in it. I even tried removing it and going back multiple times expecting the fire spitting Audi to appear only to see the same little green Jeep staring back at me.

I am sad Rockstar, please fix.