Had this problem today as a companion pass traveler. Main traveler checked in with no issue. (A 30) I saw tickets are still for sale, so I cancelled my ticket and repurchased it. *** - It allowed me to checkin with the new confirmation # with no issues. - Spouse got A 30 while I got A 58. - Fortunately this itinerary seems really easy to get a decent position.

*** Of course I could only cancel/re-book since I am a free companion. (As usual) Ticket prices have tripled. So anyone else would be better off paying for an upgraded seat if they cared about boarding position. - Technically I took an unnecessary risk, when my spouse could have most likely saved me a seat with no issue. - Of course there is technically "No saving seats" but how often do you see this followed in practice?

Doubt any of these are related, but as a data point:

1. On my original tickets I input my Precheck information. When re-booking my return ticket, I left secure traveler blank. I am travelling BACK to the US from Cancun,so pre-check is not supposed to do anything for me anyways. My TSA Precheck info did get me expedited security flying out of the US to Cancun. Spouse has Global Entry, and had no issues.

2. A southwest RR number is present on my reservation, and it doesn't let me alter it since it is part of my companion information. - It does NOT seem to match the southwest RR number on my profile when I login. (So is either from an old profile or incorrect all-together?)

3. I did enter my full name including my middle name both times I made the reservation(s).

4. Non-stop flights with no delays currently.