Vancouver has quite a lot of short taxiways that feed into other short taxiways with numerous sharp(er) turns. From where the heavies park in YVR, there ends up being a lot of brake use, especially if the 26's are active, and especially so if they have to taxi for 26L.
Right now, there is some construction work at the threshold of 26L that normally results in "stop-and-go" traffic on the taxiway, before taxiing a slalom course to the runway. I loathe using the brakes when I don't have to, but in and around that part of Vancouver right now, you have to.
Also, as Piltdown Man mentioned, brakes reach their maximum temperature sometime after they have been used, with 10 to 20 minutes being an average figure for the types I've flown.
So departing YVR off of 26L with any stop-and-go behind other traffic, into the slalom and then maybe holding in position for another heavy in front, and yeah this makes a lot of sense. Certainly not an incident as that is what the BA crew would have been trying to prevent!