Ok, the wax explains it. My Dacron is very heavily waxed, but the FF is not. Maybe wax will help, but I haven't had any issues so far. What kind of wax works with synthetic strings?
I gave up on continuous loop because I had a hard time getting equal tension in the strands, and because Flemish Strings are less massive and more elegant IMO.
I've never been able to figure out how you can put a Flemish loop on each end of the string. An eye splice yes, but that's different.