I found a glitch on EF this morning. I was looking at ATL-BOS flights on DL and saw RU/RP = 9 on flight 1200, which seemed pretty unlikely, but it was on a 738 after a holiday weekend, so I figured it was possible. I called in to re-book to that flight because the first leg of my previous itinerary had been delayed and was causing an illegal connection. However, when I re-booked, I was placed onto an upgrade waitlist of 34 passengers, and the RU/RP inventory had magically disappeared within minutes. Any ideas what happened? I thought if RU/RP was available, then it should mean that any Medallions on the flight within their upgrade windows should have already been upgraded, which would mean that there shouldn't be a waitlist. Did EF "imagine" upgrade inventory?