I found a related PR 76 in the pagure.io/pagure-importer repo.

Not sure it helps.

ping

Is it possible to move / transfer (or at least copy) an issue between different projects in the same group (or even between different groups) using the web interface?

The short answer to this is: no, that doesn't exist atm. I wouldn't be surprised
if there is already an RFE for this though.

Thanks for responding. By RFEs you mean these issues?
https://pagure.io/pagure/issues?status=Open&tags=RFE&close_status=

If so, I failed to find anything related here. If you could guide me into the something specific, I would be grateful.