Need flights IAD to LAX 12/15 or 12/16 out, return 12/21. First Class.

I'm a AA and B6 flier. No nothing of UA fwiw.

2 or 3 days ago found UA #667, 767-300 (76L) w/flat beds, or
UA #2276, 767-300 (76L) w/flat beds 12/15. But only that date, Wednesday.
Great. But none for the return.

Now it's not showing those flat beds for sale at all. Weird? ? ?
It's still showing those flights and equipment, but not in first.
Am I searching during some kind of IT upgrade/update?

I would love flat beds out of WAS to LAX.
UA seemed liked an option. But even when I could find lay flats outbound, couldn't find them back 12/21. Weird. All narrow body, w/o lie flats coming back.
Is this normal?
What am I missing?

The lay flats will likely be needed more on the way back fwiw.

What is up with no lay flats on way back, LAX to IAD?

We are closer to DCA, and are of course assessing all options.

Have looked at all options out of DCA also, AA - A321neo, Delta 757 (delta one), AK - A321, etc
Delta wants $2100 -3100 for d/o. Yeah, not for 3 passengers.

I'm tempted to go with Alaska, DCA to LAX w/return, A321. Obviously no lay flats, but ...
Prices similar. I've read at least AK crew still are pleasant and accommodating.
And the food is some of the best of domestic carriers.

Where is my UA 76L lay flats on return to IAD?

I welcome all input.

Thanks