Glad you like it, thanks for the input. I retired my addons last weekend, they'll stay online as long as possible, but you may be interested in the just-released userscript version of Copy Selected Links: https://greasyfork.org/en/scripts/469506-copy-selected-links
Its UX is a little different but I found it quite interesting to develop and start using, and it seems to work more reliably for me. If userscripts are within your abilities to install and use, I'd actually appreciate a first user and initial feedback. I use CSL, DID, and IBCP myself so I'm actually interested in keeping those maintained as userscripts without all the hassle of publishing whole addons on the big addon stores.

This is typically something to report on the bug tracker, not valid review content as per AMO rules, so thanks for not weaponizing stars. But it's impossible to have a discussion here, so if you want follow-up, you'll need to go to gitlab.
A few other people have reported the same problem, but I can't reproduce it (and I use my addons myself, so...), but they all seem to do special things like running extremely old versions of firefox or using the tor browser. I really can't support cases outside the 99%, sorry.