At well over 6,000 pounds, the Mercedes-AMG G65 was no flyweight. But the 6.0-liter twin-turbo V12 made it pretty darn fast. Too fast, in fact… particularly when driving in reverse. So Mercedes has had to recall a handful of them to keep them from speeding away backwards and toppling over.

According to the statement released by the National Highway Traffic Safety Administration, “These vehicles may be equipped with the incorrect reverse speed limitation software. While in reverse, any abrupt changes in steering while exceeding 16 MPH may cause the vehicle to become unstable.” To fix the problem, the manufacturer will be updating the engine control software to limit the vehicle’s speed in reverse.

As rare a beast as it is, the recall affects all of 20 vehicles in the United States. They were the top version of the previous long-running Geländewagen, boasting 621 horsepower (463 kW) and 731 lb-ft (991 Nm) of torque. Channeled to all four wheels through a seven-speed automatic transmission, it could rocket to 60 mph (96 km/h) from a standstill in just 5.1 seconds. Not too shabby for a truck tipping the scales at 6,250 pounds (2,835 kg) – a good 770 lbs (400 kg) more than the new G63, or close to twice the weight of the (much) smaller GLA.

It was also hugely expensive, retailing for north of $200,000 – territory in which few SUVs have dared to tread. Models like the Bentley Bentayga and Rolls-Royce Cullinan, which happen to be two of the only other sport-utes on the market with twelve-cylinder engines. With the arrival of the all-new G-Class, Daimler is consigning the big V12 to Maybach models almost exclusively. So the next model – be it based on the G or the GLS – could prove even more expensive.