We are currently evaluating this issue and will update this article when we have more information.

As a temporary solution, edit your track to not include staffing resources, then add staffing resources separately:
  1. Navigate to Sales > Group Sales
  2. At top left click Tracks, then select your Track
  3. Click Resources tab
  4. Underneath Staffing resources, click drop down next to each item and select Delete
  5. From the itinerary, schedule the staffing resources separately