Builds were failing because the HD space was 100% used up. The /srv folder was taking 80% of all disk space over 40 different build directories. After deleting all folders, build continued as normal.
The build directories definitely needs to be cleaned up, but I could think of a few situations where you might want to keep the immediate build files (if it failed) for a small amount of time to be able to debug. I propose that we have some kind of build number limit or space limit and if the it goes over that threshold, to delete the oldest build directory.
In the meantime, I can add a small script that deletes every folder except the latest 5 in my build plan.