TeamCity - GitVersion generates the build number unexpected

I have the git commits and the tags as below

The tag of the latest commit is 12.0.0-beta.6. When I run GitVersion, the result is as below

So the build number on TeamCity should be 12.0.0-beta.6, but I don't know why the GitVersion generates build number 12.0.0-beta.6+8 on TeamCity.

My build steps are as below

Does anyone know why GitVersion generates the redundant "+8" after the FullSemVer? How to remove this dedundant "+8"? Thank you very much.

The +8 is metadata and not actually part of the version number. In the documentation for the version variables, BuildMetaData is described as:

The build metadata, usually representing number of commits since the VersionSourceSha.

You can see the same value 8 exposed as CommitsSinceVersionSouce and this should increase with every commit made to the branch since its "version source", which in this case is the tag 12.0.0-beta.6 made on commit 549a1d.

The metadata does not increase with every build, but with every commit. I can see how the current language is confusing and the name BuildMetaData does not help. Since BuildMetaData is an exposed variable, we can't change its name, but I've submitted a PR that will hopefully clarify its documentation.