The hose was fitted to the cap, to me it looks like the hose slipped off the first barb and then broke on the area where the second barb was biting into the inner section hose.
I did some inspectigating on the hose today, I split the hose with a blade and found that the end section of the hose has delaminated about 2". The outer hose folded back with ease.
I assume this is a manufacture defect.
The steel braided stuff is harder to get onto the push fit ends. The problem with push fit in general is the hose should match the ends or it'll be an **** to install. It's either that or use proper braided hose and ends and swear a lot though.