Fetching Using --branch Gives Tag Error

Using fetch_linux_amd64 to fetch a copy of my repo by branch name using OAuth token. So the command I am using is the below:

./fetch_linux_amd64 --repo="https://github.com/AAA/REPO_A" --branch="master" ./LOCAL_REPO_A

The error that it's returning is:
ERROR: Error occurred while computing latest tag that satisfies version contraint expression: -1 - Malformed version: testing_fix-multi-netif-ctrl-tab_07_06

"testing_fix-multi-netif-ctrl-tab_07_06" in the error is a pre-release tag that I had created on the repo. I am confused as to why it's even computing/checking tag names because I want to fetch the repo by branch name and had specified using --branch option. When I tried other branch names besides master I got the same error.

Then I tried the original command and substituted --branch with --tag, see below:
./fetch_linux_amd64 --repo="https://github.com/AAA/REPO_A" --tag="master" ./LOCAL_REPO_A

It seems that the new command was able to fetch the master branch of my repo. I am confused as to why the --tag would work but --branch didn't work. This seems like a bug.