Space Wagon timing belts torn multiple times

Hello, someone has an explanation for this: Mitsubishi Space Wagon (Bj.93) bought. On purchase was changed by master workshop of the timing belts. After 3 years and 75 TKm tooth belt crack, vehicle scrapped. Purchase of a second space wagon (Bj.96), again changed when buying master workshop (other city, other contract workshop) of the timing belts. This time again after three years and 62 TKm , the same case, only a few days before I made the change beforehand, so before the pre-sc In both cases, the small timing belt, which drives the balancing shaft, was always torn. This was probably hurled after the crack under the large timing belts , which then skipped – consequence:capital engine damage. Strange is that the large timing belt was ok every time, so without visible damage and the small looked like sucked out and torn. It was also no damage to turning wheels or other, on the dental equipment After head repair, the motor runs again like witch, so the reason was definitely this ominous little timing belt. It may be that in these timing belt replacement sets of Mitsubishi for the workshops, the small timing belt is a garbage part, so not the original or an equivalent part released for the 90 TKm is included. In my opinion, as the small timing belt looked like, the part can never hold 90 TKm. But – according to the workshop. Can one have so much bad luck on a bunch with a car type?