I think that what FeedbirdNiner sees in MMB must be correct, judging from their acceptance that they don't have the status to select 62J or 62K.

But what I find slightly odd is that FeedbirdNiner can see the seats as available via EF. Normally, the state of the seat map returned to EF and displayed by EF is governed by the frequent flyer status that's been sent by EF when requesting the seat map. If a Blue asks for a 747 UD seat map, it shouldn't show as available any seats that couldn't be paid for. But if a Gold asks for the same seat map, all of those seats should show as available. (Assuming, in both cases, that they're not actually occupied already.)