Bought a large roll of pull cord which was listed as PREMIUM. White outer jacket with red hash marks. Have installed many new cords over the years, but have never had this problem. There are approx five nylon leader cords running through this soft white with red hash mark jacket. I have had the jacket to pull free of the knot four times. Twice on the spool end and twice on the pull grip end. When it pulls loose, the inner cords are still connected both ends, but the jacket scoots all the way to the opposite end of the pull through. Disgusting. Am I dealing with something new that I don't prepare the knots correctly on or what?