I gave FFXIII 3 shots, putting in over 40h in total. The farthest I got was about halfway through, two years ago. I hated the game so much, that I actually stopped playing games altogether for like three months. It was completely miserable. I’m a certified FFXIII hater.
If I understand it correctly from the reddit post, this was a popular mod, that you could get directly in-game, so probably available through the Steam Workshop or something. In that case you assume everything is fine and don’t really check out, if there’s something wrong.