They have a gui wrapper with SNAP also for upgrades that uses some 'automated' system for requesting and reissuing (my experience is hit or miss with it working properly, sort of like the self-upgrade request with ruc/guc at booking)... but that wouldn't require being put on hold.
Something sounds fishy with the 'system' not allowing a reissue as that is a manual process through DLTerm, unless somebody tried being lazy and used the SNAP wrapper interface and got rejected.

Had an RUC waitlisted (called in, not via the checkbox on booking) on a flight in two weeks, Z space opened today but booking was still showing me in C+ so called in, agent told me it's cleared but "still processing", put me on hold for ~8 minutes and pulled the RUC and reissued the ticket in OL without me asking. So looks like there's still a way for them to reissue even more than 3 days out, assuming you get the right phone agent...

Glad to see another datapoint on this. I’ve run into this same issue for the last 9-12 months or so. Sometimes the agents quote a 3 day rule, others quote a 24 hour rule.

Nothing like consistent inconsistency.

I posted this in a different thread and didn’t get much response.

I just booked roundtrip BOS-HNL-BOS nonstop for Dec into Jan 2025 in Main Cabin using Delta Reserve Companion Certificate, PM so auto upgraded us to Comfort+, called and applied 4 RUCs for my partner and I, 3 cleared to D1. Asked them to "long sell" for the fourth ticket, wouldn't do it. HUCA the second time and success, took 45 minutes all together for them to reissue the ticket. It's been reissued with a new ticket number, however it's showing in OX. Was it reissued correctly? Are we good, or is there still a possibility of equipment change and being bumped out of D1?

Mind you, these were showing as Z fares.

This is currently on a lousy 763, but a lie-flat nonetheless.

As long as eticket receipt shows an O- class, you will be fine. Agent used wrong class but it’s all manually reissued and as long as it’s O it will stick.

OX is the correct bucket for D1 RUCs I believe.

When I search for flights on delta.com, while logged in, I am suddenly seeing lots of flight pairs without the upgrade certificate indicator, while other flights in the same search have the indicator. Has anyone else run into this? Any workarounds?

For my trip JFK-SFO which RUC had cleared, I noticed there were 17 seats open. So, I decided to call in and see if they can redeposit the RUC and put me back in main cabin.
Agent #1: I spoke with my supervisor and we can't do that.
Agent #2: He put me on hold with another team. I hung up.
Agent #3: Sir, I need to uncheck you in order to try. Me: Go ahead. Agent: I am working with another department but it looks like we aren't able to put you back in main cabin. Me: Thanks for trying. Let's leave it as is.
After hanging up, I'm unable to check back in. Call again and explain what happened. I just want help to check back in.
Agent #4: Let me work on it. She gets her supervisor to take a look and he tells her it's wide open. Save the RUC. They work their magic and I'm back in main cabin. She tells me the RUC will be put back in my wallet in a few days.(I'm already planning to call to have it redeposited).
2 days go by and I check my wallet and the RUC is there. I'm shocked.
As for the upgrade, was #2 for 17 seats. Then, on the day of the flight, #1 for 4 seats. I don't know what happened to 13 seats. Just vanished. This was my first complimentary upgrade to D1. Agent #4 and her co-worker saved a RUC for me. And I got the upgrade. I'm very grateful!

This usually happens if your trip includes any non-DL metal flight.

In my experience, this is pretty typical on the premium transcons (especially JFK-LAX), and why it’s so hard to clear without using a GUC/RUC

SDC from earlier/later flights, Last minute D1 purchases, and IRROPS from an earlier flight could all cause drastic drops in available FC/D1 seats day of prior to upgrades being processed.

I am primarily seeing this with DL metal, domestic flights. It's very odd. Sometimes if I reload the page, I can get the indicator to appear for more flights, but never all of the flights on the results list. Example below.

https://cimg1.ibsrv.net/gimg/www.fly...d05f210685.jpg

I have been noticing this as well. One or two flights show the "First Available...." but the rest, no! The flights I was looking at were all on DL metal. Weird!!!!

I had the same issue last week. It's like the first batch of flight options doesn't load correctly, but once you go down the list and load more, all of those will load as they should showing RUC/GUC availability for each one. It's clearly some kind of coding issue.