It looks to be dead in line, so .... probable causes ..... ?
FACT:
Rubber UJ is ripped apart in this car.
FACT:
Rubber UJs last 100k miles or more in most cars.
FACT:
There's a right way round to fit rubber UJs - and a wrong way round too.
SO?:
Excessive stresses and strains must be the cause of failures if the Joints were OK to start with AND WERE PROPERLY FITTED.
It is next to impossible to cause excess rotation stresses on these UJs , but excess ANGLES would be bad, but yours seems OK, which leaves us wondering about fore-and-aft telescoping problems ......
CharlesY