As when dealing with high-stranding issues, we must consider that all the yarns within each strand have an identical length. However. it may happen that one strand yarn is longer.

There may be several reasons for this unfortunate state of things:

1. • when making rope with traditional methods (with a rope-making machine or method similar to those used in rope walks, for instance), when the last length of yarn is tied to  the hook, some unintended slack is introduced while tying the knot, making that last yarn length slightly longer than the others. This can be prevented by checking proper length and tension of yarns when twisting the strands, as shown here
   

1. • in case of industrial production, one of the spool might not deliver its  yarn under the same tension as the other spools - this is however only my hypothesis, which i can’t check for the moment, as i have no access to such fabrication processes.
   

Another contributing factor may lie in the quality of the yarn itself.

A proper yarn should be spun in such a way that it is cylindrical, smooth and consistent in its thickness.

Sometimes a yarn may present irregularities in term of thickness; some short segments may be thicker, causing the yarn to stick out of the strand, and be prone to snag.