Vocalist Cam Pipes was originally only invited to record background clean vocals for select tracks after the recording process was mostly complete, However the band liked the idea of having him on board full-time and so he recorded more vocals which were dubbed over the rest of the songs before it reached its release.
Cam Pipes, initially invited to record only background vocals on select tracks after recording was mostly finished, eventually became a full-time member of the band and recorded additional vocals that were layered over existing songs before release.