Air lines are often the culprit when it comes to slow leaks. Most often, leaks are a result from lines not squarely cut and flush inside fittings. One has to ensure air lines are squarely cut. Tube cutters are the only tool to use IMO. Even then, you have to be careful not to compress the plastic tubing as you cut as this will result in out-of-square cut. Box cutters, tin snips, etc will not likely make a square cut.
I deal with pushlock air fittings alot at work, I do have a very good pair of tubing cutters.
For years I used a razorblade or box cutter, be careful and you can get it square, make sure therre are not any burrs.
What works good is a cigar cutter, mostly for trimming the end to square it up.
The OP has leaks from the bags themselves, so no amount of work on the lines will fix it.