Arrows show even when disabled

Hi jennypanighetti, thank you for your report! I think it was made on purpose, because GLightbox is popup slider. But I agree, it's redundant functionality for one image popup. I added opacity: 0 for disabled arrows and released 3.2.1 version for GLightbox fork:
https://github.com/levmyshkin/glightbox/releases/tag/3.2.1

Thanks so much for the quick fix! However, I can't seem to get the library change recognized in my browser. I did update the library to version 3.2.1 by going to the module's folder and running composer install from there, and I see the updated CSS file in my repository, and I've cleared all the caches, but the browser still shows opacity of 0.1. I'm wondering if the module needs a version increase to reset the libraries version to clear the caches?

You don't need to update levmyshkin/glightbox library manually if you already have composer. Just run:
composer drupal/glightbox -W
or
composer drupal/glightbox --with-all-dependencies

It will update library from github automatically. As I see glightbox.min.css file was updated in 3.2.1 version:
https://github.com/levmyshkin/glightbox/releases/tag/3.2.1
https://github.com/levmyshkin/glightbox/blob/master/dist/css/glightbox.m...

Aha! That's right, -W would force the update. Thank you!!