Bad fuel.
I'll verify this as much as I can. Spoke with an AC Jazz crew yesterday that said YVR was a mess because the fuel from the farm was contaminated. Only fuel that was uploaded into the fuel trucks the day prior and tested was allowed to be uploaded. Accorcding to the Jazz crew, because of the quantity of "clean" fuel available, only Jazz aircraft were fueled and the AC mainline aircraft were left without which left all the Asian bound ships grounded. Quite possibly the SKYW bird couldn't get a full load of gas and had to head to SEA to top off. Seems like something our dispatchers would do under those circumstances. They are pretty resourceful in our dispatch department. I don't know that for a fact, just my personal speculation.
A very bad break for AC and Jazz. I feel bad for those folks because all of the Jazz and mainline crews (they do some painting of their birds in my town) that I have met are top notch folks.
OOramperpilot