Obviously you are correct, have rectified the situation by using heat and screw on clamps, just came back from a 1500 mile trip and no problems at all...The Push Lok connectors have been around for 30 years I think. Now there are definitely knock offs of those, and so many hose types, it's tough to sort out. It sounds like the hose you used were not appropriate for the Push Lok's.
OEM fuel lines in the 80's relied on the plastic materials, and were hell to install on the barbed end fittings. Heating was a must, and they were just less than hell to install then. I've messed with those enough that I will try hard to never use plastic lines again.