For international fares, Basic Economy uses the same booking codes and so Matrix will show you the lowest (BE) fare by default. The $1,457 price is Basic Economy (-LGT fare type). Regular Economy costs an extra $90 per direction, and prices like this (note the -NCV fares and $90 price increase):



There are two complicating factors to your search on the United website.

The first is that the outbound flight does not have V inventory. To make life more confusing, United has started a program where it will sell fares without valid inventory by taking the "true" prevailing price and discounting it: https://www.flyertalk.com/forum/unit...iscussion.html

In the below example, United offers a $6 discount from the published Q fare to book into V class and be bound by the rules of the V fare. This price cannot be replicated on Matrix or any other GDS, but NDC systems like Google Flights will show the price. However, it is normally a relatively nominal discount ($6 on about $700 here).


Second, your account seems to have access to private fares, maybe through Break From Business? The private designator on your search /B405 and similar indicates you are seeing lower, private fares which are unique to your MileagePlus account. That is why your prices are very slightly lower than the ones I see.