From one of the photos, the cable spec "G657A2" is visible on the outside - and specs listed for that indicate it's "bending insensitive single-mode fibre", apparently it can tolerate 10 loops around 15mm mandrel. (Which does surprise me).

But yes, agreed, a lot of "Er... why would you do it like that?" bits.

Those 10 loops definitely only apply to the single mode fibre itself, not the entire assembly with armor and everything, because that's just... physically impossible.

Cables for direct burial only like to be bent once or twice, and then only gently. Anything else may very well break the armor (whether plastic or metal), after which all bets are off.

Still, for the outer jacket to become brittle to the extent described, something else is required, which may very well turn out to be "shoddy manufacturing"...