ArieTonight's TF2 update came right at the time a lot of people launch their EU matches (21:00 CEST), the update was large and the steam servers for server downloads slow or at least varying wildly in performance. This caused the update to take anywhere between 2 and 20 minutes. These long update times were experienced on servers from all the geographical regions we provide.
Since people are used to <5 second server boot times, many people ended their reservations within a few minutes (while the update was still running), and made new ones. This didn't help the situation as this had a chance of triggering a bug in Valve's steam server update tool causing the update process to freeze while trying to shut down, this left a handful of servers in this frozen state.
Luckily it seems everyone managed to get a working server within 15 minutes or so, but I'm not yet sure how to improve this situation. If an update drops close to match times, is big, and steam is slow, we're going to have a bad time.
luckily this can only happen once every couple years ;-;