Series VI Supercharger Vacuum Line

[Cwarre9]

I have a vacuum leak that sounds like it's coming from the back of the supercharger near the firewall. There's a vacuum line that runs from the supercharger bypass valve to a vacuum line off what looks like the brake master cylinder. The length is short enough that it could be a single section of hose. However, there's a plastic coupling in the line. Since the run is so short, I'm wondering if the plastic fitting is a reducer or some other form of control to manage vacuum levels on the bypass valve. (Photo attached). Maybe they just ran out of hose, but I doubt it. Any thoughts are appreciated.