This is my scenario:
We are working on v1.0.0 and on vnext. We are currently releasing v1.0.0-rc3. The repo contains a master branch branch for v1, and a vnext branch for a post-v1 release. We have issues on a v1.0.0-rc3 milestone, and we have issues on a vnext milestone. We just made a v1.0.0-rc3 tag on the master branch.
When I generated the changelog, it included the issues from the vnext branch. This is not what it should be doing. Those issues are attached to an open milestone.
The generator should be smarter about the milestone. All my milestones have the same name as the tag that is later applied (and the release that is later created on Github). If issues are part of a unreleased milestone, don't include them on any tag. And it should correlate the issues, tags and milestone, for an accurate changelog to be produced.

If you'd like to take a look at the setup: Code-Cracker