I get this as well. I'm by no means an expert but I've studied the hows and whys pretty closely. The way I "deal with it" is to serve the loop portion and then rotate the posts closed, line up the loop servings on the outer posts (or on my tensioning jig hooks) and "stretch" the strings. "Stretch" is a misnomer at this stage of the build as you are not really stretching but "evening out" the tension to get all the courses of your layout to more or less even tension. Since there is only about 3/4" to 1" of serving at each end there is enough give. After a few minutes under this tension, I'll start serving the end loops closed for about 20 rotations of the serving jig, then crank up the tension for another 20 wraps, then put in my 20 or so twists and crank up the tension and finish serving out the length I need. Since I adopted this methodology I have had no individual strands any looser than other in the bundle.Also, no matter how much I pay attention to making sure I have even tension on the string when I am wraping it around the post somewhere along the way I seem to have one strand be loose. Any ideas what I am doing wrong?