xmatch | Simple pattern matching for ES6 | Script Programming library

Consider a very simple example of a dynamic range:

Cell C10 (arbitrary cell):

Consider a very basic table:

I'm using a modified match function since years which worked fine. But suddenly I get runtime error 13 for no reason. This function is called two times in the actual process before the error pops up. The first time everything works fine, the second time I get the error. Here's the code:

I think I made a breakthrough with "ultra-dynamic" ranges. That's how I call them because not only they are dynamic; but also they refer to different ranges based on the cell address in which they are written in! Now I need to advance this breakthrough even further. Those of you using dynamic ranges in Excel, especially the dynamic-range-gurus, will be thrilled to read below and can possibly help in this advancement:

Disclaimer: If you are not familiar with dynamic ranges do not attempt to read below!

Background: Our sheet has cells with calculations on top and a pivot table below. Each cell above refers to the pivot table cells below in the same column. The first column of the pivot table (titled "Row Labels" by default) is sorted from top to bottom in descending order. Each of the next columns has the result of a different test. At one point somewhere in the middle rows of the pivot table there is a "marker line" that separates the top part of the pivot from the bottom one. Let's call the top part "Uppers" and the bottom part "Downers". Let's call both parts together "Population". Population is a non-contiguous range because the "marker line" that separates the Uppers from the Downers intervenes.

For each cell above the pivot there are calculations for the pivot column exactly below that need to refer to the Uppers or Downers or Population of the column itself.

Previously, my formulas in all of the cells above were a repetition of something like this below:

What array formula will return values which don't appear in another list?

Example: Cells named ShortList contain (one word per cell):

I am facing an issue to find all strings which have first few (>=2) characters repeated twice in a string in R language.
E.g

The strings should select out
(1) allochirally ------> first 3 characters 'all' repeated twice in string
(2) froufrou ------> first 4 characters 'frou' repeated twice in string
(3) undergrounder ------> first 5 characters 'under' repeated twice in string

The strings should NOT select out
(1) gummage ------> even first character 'g' repeated twice, but only 1 character, not match condition as >=2 first characters
(2) hypergoddess ------> no first few characters repeated twice
(3) kgashga ------> even 'ga' repeated twice, but not including the first character 'k', not match condition which require including the first character

Heard about backreference (e.g \b or \w) might be helpful, but still not able to figure out, could you help to figure out ?

Note: I see there is a function as xmatch <- str_extract_all(x, regex) == x as the method to use, the str_extract_all from library(stringr)