So I posted a separate thread last night on this, but haven't seen anyone chime in. I should have probably posed here in any case.

I was trying to book an award ticket. As the website says, "MileagePlus Premier members and MileagePlus credit cardholders have access to last-seat availability on Standard Awards."

On the flights that I was trying to book, there was plenty of Y and YN availability. The website would not however let me book these flights so I ended up calling reservations to book the flight.

Is this a system glitch?