Bug concatenating member of large array with string

[Joe Pater]

The attached bash script (named 'test'), when run on my laptop,
produces the following output:

xyzerg

Instead of the expected:

Aabergxyz

I don't think this error occurs on my PC (I can't test it at the
moment as I am away), but it happens consistently on my laptop.

uname -a:

Linux localhost.localdomain 5.13.7-200.fc34.x86_64 #1 SMP Sat Jul 31
14:10:16 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

bash --version:

GNU bash, version 5.1.0(1)-release (x86_64-redhat-linux-gnu)
Copyright (C) 2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.


(Note: I tried to do a bisection, and the error was still persistent
in version 4.4. I gave up going further back due to compiler errors)

test
Description: Text document

file
Description: Text document