I've tried tagging MuffinLibPTSets to get a Release, but it keeps producing alphas. The documentation states:
A version string is the name you give your tags when you do a right click -> tag/branch. If this name contains only dots and digits and optionally starts with the letter v (such as "v1.2.3" or "v1.23" or "3.2") or contains the word "release", then it is considered a release tag and a release zip will be created. If the above conditions don't match, it is considered a beta tag and a beta zip will be created. All other commits (that are not tagged) are alphas and alpha zips will be created.
I have tried various combinations of that without any luck.
I'm not seeing any recent Alpha versions for that project; not even deleted files. I manually added the project to the packager queue, which showed "Skipping zip for wow/libpt-muffinsets/mainline, it has a new alpha build but is set to package Release only." At that point, I cloned your repository and found that the latest tag is "6.2.0.02" which was added on October 26th.
Perhaps you aren't pushing your tag? That is a completely separate action from commit pushes in Git.
I do have a similar problem with the packager when Tagging via Curseforge. It seems to create the release properly but it's not available until i commit another alpha. Then it overtakes the newest alpha as though the release is the newest version which it isn't. And to be clear i'm using Subversion.