Currently, if a project has lightweight tags, the tagname is not shown in the releases page. For example from https://pagure.io/fedpkg/releases
I honestly don't know if that's something we can fix ourself, I fear that would be something to fix at the pygit2 level and since pygit2 is a pain to deal with and will never be updated in rhel7 (what runs pagure.io), even if it was fixed, I don't know if we could run it.
Commit ee578c67 fixes this issue