We are primarily supporting the server-side parts, then the script itself is open source. It happens that we do fixes with the script, but it's not always our highest priority. To elaborate - In general, it might take us quite some time to discover these issues, and then we might not have the time to fix it right away.
You have however reported it, with a workaround, which is superb. But it seems that we are not getting any notifications on the feedback made at Greasyfork. The script itself is maintained at GitHub (
https://github.com/magma1447/greasemonkey-geocaching-projectgc). We are getting notified with issues raised there, and we also try to review and prioritize them.
If you wish, you are free to make a pull request at GitHub and we will accept it into master and make a new release. Otherwise we will look into it in the near future.
Don't read the following as criticism, just as information. I really realize that you have tried your best to help, and we are grateful for that. It's awesome that you figured out the issue and provided a short fix.
https://project-gc.com/Home/UserScript does hint on that the script itself is open source, and that we welcome updates/patches.