Yesterday I went to United's site to buy a RT refundable ticket from IAD to LAX for a week from today. Fare was $1038, pretty good for refundable on this route in my experience. I expected coach, but whne I got my final itinerary on the screen it showed first class for the IAD-LAX flight! I couldn't believe it, this has never happened before. I treid every flight on the LAX-IAD portion and couldn't get first class to come up for that fare- I woudl have had to pay full first class fare to get both legs in FC. When I printed the receipt (which I had to go to my stored intineraries on the website to do, this was different also) it had the flight as "discounted first class". What's up, have I been missing out on this in the past or is this "discounted first class" something new?

Sounds like it might be a QUP fare. These do come up on occasion, but they aren't always predictable. Look at the fare basis for your ticket; if it's Q, then that's what happened. I got one when searching recently for an ORD-ATL ticket, but when I went to buy it, it was no longer available. There are some posts about this on flytertalk.

Yes, it is indeed a Q. Now I need to figure out how to explain to the client (who won't pay for FC) how this happened, that I lucked out and what a good deal it is. I didn't think of that when I got excited and bought the ticket! I printed out a refundable RT coach fare (same as what I paid) so maybe that will be enough for them.
I will check flyertalk. Thanks very much.

Go to 'my itineraries' then select the specific trip and 'view itinerary.' When the itinerary comes up, then click on 'fare rules' for the QUP portion of the trip. That may provide you with something that explains the type of ticket to share with your client. I don't have any QUPs in my itineraries right now, so I can't say for sure, but it's worth taking a look at. 'My itineraries' doesn't seem to be working very well today (good ole ual.com), so you might have to try this later.

lucky you. will have one for you at the hono gtg.

What's not to believe? Paying that price, you better get first class. Continental also give you confirmed upgrades for "Y" fares on many routes before you purchase. And often a FC ticket cost about the same.

UA's simply doing the same here.