Incident Feeder Form - Fields not clearing when changing primary contact

We found that the selected item fields for Location, Department and Equipment are not cleared if the primary user is changed prior to submitting an incident.

The Department and Location workflow was simple enough to clear but I am looking for a way to clear the Selected Equipment.

So far I have found a number or variables relating to TicketCI's but cannot find the one that clears the selected equipment when changing the primary contact