The server time was indeed adjusted.
For grins and giggles I went through most of the public zones and checked the server clocks, they're all correct. Dailies are still reset at the same time, Tempest happens at the same time. The only thing that is different is siegewar, which I suspect is their way of saying "ah, it was broken last time because we changed the clocks AND siegewar time last year so it was one hour too late, so this time we're fixing it". I have a message in to confirm, but I'm pretty sure this is it.
So come to find out that possibly the siegewar time was broken after last time changed and fixed a maintenance later, so it is indeed wrong. I believe we're getting this fixed during a maintenance, if not this week, definitely next week.