Was attempting to book/price a fully refundable open-jaw fare and UA.com is being...weird... (Including after selecting the outbound flight showing me 48 option for the return with "Not Available" in the first and economy for every single option a few times in a row)

Finally got (what I thought) was complete itinerary but noticed the 'non-refundable' language in the checkout flow... Pulling the fare rules (basis BAA0AFFN/PC01 outbound and LAA4JKFS return) I'm noticing something I've never seen before:

"VALID FOR ADULT. THIS FARE IS VALID FOR A SPECIFIED ACCOUNT CODE. CONTACT CARRIER FOR DETAILS."

(well... also I've never noticed the "any UA flight but not nonstop UA flights" but I can actually understand that one )

What does UA mean for "valid for a specified account code"?

My first guess is corporate accounts -- but I have none (unless you count the PerksPlus account I manage)

I'm also used to N in the last character of the fare basis indicating a non-refundable fare (and from the rest of the rules this doesn't read like a refundable fare -- e.g. there's no requirement for a "REFUNDABLE" endorsement) so a little interested that this is what it came up with when my search when I told UA.com to show me refundable fares .