I know this project is 💀 but we use it on some legacy repositories hence I'm reporting this.
When we use captain build in a branch, it creates a tag for master. The problem was introduced with the following commit:
29f59eb
Example:
circleci@0d4777e529b0:~/project$ git symbolic-ref --short -q HEAD
staging-db-wip
circleci@0d4777e529b0:~/project$ git name-rev --name-only HEAD
master