There is something odd going on with YVR-LHR at the moment.

I am looking to get a UUA to F and have been checking daily for months. Up to two weeks ago LHR-YVR and YVR-LHR F seats were being released for up to the following seven days. Suddenly this switched to no seats at all. No on the day, day before, nothing.

There has been a buy J get F one way promotion and premium fares sales. However, unless the whole F cabin is sold out (and seat maps I have looked at do not bear this out), they used to release F reward seats at the last minute. Perhaps they are holding them for Op-Ups.

However, this does look very odd to me.