Your Yomud juval shows the peculiar jog in pattern that you pointed out as being fairly common - occurring in 6 pieces in your own collection. For convenience, here it is again:

I notice that there is an odd color change in one section of the main border very near the odd knot. Is this a common feature as well? Or, perhaps, this is a restored spot.

Regards,

Steve Price

Regards, Yon

The above Yomud shows a single knot in the border misplaced.
I remember reading a speculation (superstition?) that unless an enclosed area, such as a border, has an opening, an evil spirit may become trapped there and remain to inhabit the owners home. The weaver will "leave an opening" for the spirit to get out. This may explain some of these single knot displacements in border systems.
If you refer back to salon 45, Crepuscule with Carpets, there is a thread entitled Some Belouch Balishts. Reply #9 shows the lower corners of one of the balishts from the salon. The left corner shows the white/brown dotted border shifts one knot over. The right side shows no such shift. The "evil spirit exit" may explain this phenomenon.
Steve Price also shows a thread in the same salon entitled Internal Elem showing a Baluch with the internal elem structure.
Even we westerners practice unexplainable superstitious behaviors, from throwing a pinch of salt over the shoulder if you spill some, throwing a penny away that you find on the ground, saying "Bless you" when someone sneezes, and so on. It is entirely likely that some similar weaver-superstitions from time beyond memory continue to be practised without contemplation elsewhere in the world.

Internally yours,

Patrick Weiler