I'm taking a companion with me on a trip this Thursday, and being primarily a Delta flyer, I initially booked us on the same PNR (that's the only way you can upgrade a companion on DL). When I found out I needed to split the records in order for me to get my EUA, I did so.

Here's the rub: there are mileage upgrade seats available now, and we're well within the 72 hour upgrade period. It's my understanding that the mileage upgrades and EUAs come from the same inventory, so I'm thinking there's something wrong with my record. FWIW, there are 12 of 16 FC seats avail on the flight, and it's IAH-CUN on a Thursday afternoon, so it's not like it's an elite-heavy flight...

Any ideas on what could be happening, and what I might be able to do to fix it? Thanks in advance.