I'm assuming that others have seen this before (although I haven't, and yes, I searched), but I'm wondering if anyone knows why:

In booking two tickets for Mrs. dstan and me, JFK-MIA-LGA, the outbound showed N2 on ExpertFlyer (thank you for the alert EF!). However, pricing the itinerary for two pax on ITA put one ticket into N and the second into the next higher fare class S. Correspondingly, as one would expect, attempting to book two pax on AA.com bumped both to the higher fare class S. Single tickets on both ITA and AA.com correctly priced into N.

"Well, duh, the inventory dropped to N1 while you were looking!", you say. Not so. I double checked EF along the way and this behavior was observed several times on the same day. Ultimately, I was able to book the two tickets on separate PNRs at the lower N fare class on AA.com. After booking the first ticket, inventory dropped to N1, and after booking the second, it dropped to N0. There was just no way to book them simultaneously into N.

The AA phone agent I called to link the upgrades could not explain why this happened, so I wonder if anyone else here can? Glitch or revenue management strategy?