Could it be that SHA/M is GS? They cleared the standby list into economy and then applied an RPU/GPU and so jumped above the 1K RPU?
For this to be true then 2, 3, 4, and 5 on the original list would have to have been GS with no instrument (but above SHA/M with tiebreakers) or 1K with instrument (but below MOR/I with tiebreakers), which doesn't seem totally unreasonable for a hub-hub flight.