Trouble using git on the host

After making changes in the gitlab-rails/ folder when I try and add, commit etc I get an error:

lee@Lees-MBP gitlab-rails % git add .
fatal: Unable to create '/Users/lee/Source/gitlab.com/gitlab-compose-kit/gitlab-rails/.git/index.lock': File exists.

Another git process seems to be running in this repository, e.g.
an editor opened by 'git commit'. Please make sure all processes
are terminated then try again. If it still fails, a git process
may have crashed in this repository earlier:
remove the file manually to continue.

Sure, I can delete the lock and move forward, but it doesn't seem right?