That page is discussing "crosstalk" on a multi layer, Printed Circuit Board. I used to make circuit boards for a living.
I spent all day loading prepreg in to a giant heated press to bond the multiple layers.
I am wondering about different crosstalkers. Maybe some are near to noisy problem crosstalk sources and others are further away from those sources.
Yes, that is likely. Remember that most crosstalk comes from other pairs within the same multi pair cable.
Pairs which are directly adjacent to each other for long distances within the multi pair cable will cause increasing levels of crosstalk.
You have 2 pairs sharing the same drop cable, twice.
A 20m run in your drop cable is nothing when you consider that your line is some 7km long. That's why you see little to no change between the lines when resyncing the surrounding lines.
With FTTC crosstalk can be much more noticeable, particularly 2 lines on a single drop cable.
I've seen someone with 80Mb sync who took out a 2nd line. This 2nd line knocks nearly 20Mb off the 1st line when synced.
The 2 pairs in question will share more than just the drop cable though and may well be in close contact within the multi pair cable all the way back to the cabinet.