Maintenance for the week of April 15:
• [COMPLETE] ESO Store and Account System for maintenance – April 16, 8:00AM EDT (12:00 UTC) - 6:00PM EDT (22:00 UTC)
If you're thinking about the blue "superb imperial reward" boxes, they don't drop runeboxes. They can drop the polymorphs but not in a rune box, so it can't be traded and once you have all the polymorphs you won't see them anymore.