Isn't that an unused hose being stored in the hose garage? If so, then it is the body of your dust deputy that is discharging, and the hose is simply acting to shorten the path of the arc.
You have an anti-static hose between your tool and the DD, but a non-anti-static hose between the DD and the Vac. Simply grounding the body of your DD should reduce the likelihood of additional discharges.