Manufacturers in Spain, France, Italy and Germany have been building at least 30,000 motorhome units a year since 2006 on the 3.5 metric ton version of that front-drive, single rear wheel chassis, branded as Ducato from FIAT or Boxer/Jumper from PSA. I've seen nothing in the press about stability problems.
However, for our market the heaviest versions of the van and the cutaway chassis are being rated a metric ton heavier, putting the platform at the conventional highest weight limit usually used here for only four wheels on the ground. There have been stability complaints about RVs on rear drive SRW platforms at these weights, leading to aftermarket DRW conversions.
With our desire to have RVs as big and fully furnished as possible, there is a tendency to overload. Our passenger vans in this category are required to have electronic stability assist programmed for roll stability. I'm not sure whether this is a feature of the RV cutaway platform sold here.