wow, that is a weird one.
AS is $452 o/w (12:30 departure)
AA is $505 for 11 am departure
UA is $62 (BE) for a 10:41 am departure.
and there is only one seat (10E) empty on the plane.
This fare has to be the result of incompetence on the part of UA's fare/IT department.
p.s. same $61 BE fare is also available on Wed 6/13, when the plane is 40% empty per the seat map.