Last night ~11PM I held 3 reservations (2 via the 'pay with cash' and 1 held using a travel voucher). I went on ~630PM tonight to confirm/pay for them and none were on my reservation page, although they all said that they would be held until midnight tonight (~25 hrs).

I called CO.com support and explained the issue. The lady said that, although the website says they are held until midnight, they are only held until 5PM. With a lot of work, she was able to re-instate them, but told me that in the future they will not do this, and that I was lucky she was able to on these reservations (2 of the 3 the fare was no longer available online, or I would have just re-booked them via co.com).

Is this a known bug? I'll report it to CO.com so that it is tracked, but it's just annoying that I had to spend 2 hours on the phone while they re-worked my itineraries that should have been saved another 5 hours.

I have observed this as well. I assume they cancelled your flight after the airport counter in your city would be closed - so it would be too late to go and pay cash for the ticket. From IAH though the airport and counters are open much later than 5pm.

Actually, I selected Western Union and, I presume, that WU stations are 24/7, so that shouldn't be an issue.

Why don't they change the verbiage, or actually fix the problem?

I asked the lady that and she didn't know why the website still says the incorrect time.

I understood that this was suppose to have been fixed ages ago. I even sent Scott examples of my reservations which suffered the same fate.

Perhaps an update was done to the back-end which introduced a code regression.

I hope they look into this.

A separate but related issue that I noticed is with the dates of reward reservations. The web site says the reservation will be held until one date and the confirming email has a different (sooner) date. I just did this yesterday and the web site said the reservation will be held until midnight Feb 17 while the confirming email said midnight on the 15th. Of course the system cancels the reservation as per the confirming email with the sooner date. It happens consistently as I'm putting reservations on hold trying to get better flights than one I have booked. I keep screen snapshots just in case it becomes an issue in the future.

So I purchased the one that the agent had to piece back together and manually insert the coupon (10%) ~13 hours ago. Inserting the coupon was an even bigger issue on the phone last night. I still haven't received an email confirmation and CO.com shows
How long should I wait before calling?

I have never had to wait more than a few hours for the eTicket Itinerary and Receipt to show up in my email, and it's usually there within 30 minutes. I'd go ahead and call if it's been that long.

So I called CO.com support and was told by Agent 2 that there was an issue because the PIN from the certificate wasn't listed on the reservation, while I gave it to Agent 1 last night when she held the reservation. The lady was great and told me that I'd have to be on hold while she got someone to attach it to the reservation. She came back and said it'd be a ~10 min hold because they were very busy. No problem.

Agent 2 came back after 12 mins and politely disconnected me. The agent immediately called me back at the # on my profile before I could re-dial to them (excellent customer service!). She said the ticket was all set and would process within the next 15 minutes. If it didn't, she said she or someone would call me back at the same number.

Six hours later, I still hadn't received an email, but got a call from Agent 3 at CO. She said they were still having issues processing the ticket because I never gave anyone the PIN. I told her that I wasn't at home with the voucher, but I gave the PIN to both Agent 1 and 2 (using their names). I told her to call me in 4 hours and I'd be at home with the PIN. She seemed annoyed with their system because I had given it to them twice and it still wasn't marked, supposedly. She apologized and told me she'd speak with a manager to have it processed and she would call me back immediately. I didn't get a call, but in ~10 minutes, I got the confirmation email... FINALLY.