French bike makers were shipping bikes as quickly as they could box them up and push them out the door! That was part of the reason they got a bad rap for cosmetic and quality issues. Items like bars and stems for example.
As Chas said, most of the French (AND British) bikes of that time period had clear quality control issues ... "just get 'em out the door to the 'Mericans!" Which is precisely why I bought a new '74 Grand Jubile ... the upper end Motos were significantly better than the Gitanes, Juenets, Peugeots and Raleighs of that time period. I really wanted a Raleigh Competition but the finish of the Raleigh frames was atrocious. Plus the Motos applied their markings via some sort of screen printing process rather than decals or foil stickers, then the whole thing was clear coated. Why the market prices for early '70s high end Raleighs is higher than comparable Motobecanes is a total mystery to me. The Motos were (IMHO) clearly better built and finished and better looking, to boot!
As far as the Pivo stems and bars go, I've never had any problems with them. I've had about 5 or 6 Grand Jubiles with both regular and randonneur style bars and have never had one sag/break/or otherwise deteriorate. On my first Grand Jubile I did split the steerer tube where it's filed flat and threaded when I tried to insert a non-French diameter stem into the steerer. It didn't split immediately, but over time it developed a crack and I replaced it with a Grand Record Reynolds 531 fork.