the rubber products that comes from china are not to good so a fuel line replacement when it is not that old is not uncommon. you can also check and see how tight the banjo bolts are . They have copper sealing washers that can also give you problems.
bolts are tight. I guess i am more used to steel fuel pipe that doesn't leak unless you mess with it. The JM has braided flexible line . I reversed the fuel line, both ends are the same, and sure enough the leak gained in volume at the “new” location. Ordered a new line Thanks for the reply. BG
what you can do is to use a die grinder with a cut off wheel split the compression sleeves the banjo fitting will come out ,they are barbed replace the fuel line with a better grade and use hose clamps.