Ill-Gotten Gains Part Two went live on GTA Online today, and unfortunately it's brought with it some technical issues, including one that's causing cars to go missing. Rockstar acknowledged the problem, in part, on its support site, although it said the cars aren't actually disappearing, they're not just where you left them.
"We have found that some players’ garages may have been rearranged after updating to 1.28," the support site states. "If you think a vehicle is missing, try calling your mechanic and scrolling through your various garages to see if the vehicle was moved to another location erroneously. If you are unable to find your vehicle, please submit a request to our support team and we will assist you."
Unfortunately, other users are reporting a different sort of disappearance: The car is gone, but the tires stay behind. A link posted on Reddit (via VG247) illustrates the problem, although it's not clear if the car (minus the tires) is actually gone, or if it's just doing an Invisible Jet routine. Rockstar also said it's received complaints about lower framerates in the game following the 1.28 update, and that it is "looking into these reports now."