Say you are doing a cap production deploy and it fails because of a code error in one of your files
Next you fix it and try to run the deploy again. It will continue to fail at the same spot and have you wondering what the hell is going on. You thought you just fixed that.
The issue actually lies in the fact that it deploys from your GIT repository. So you must add, commit, and push your new changes to GIT then run your cap production deploy.
Voila its now working!