Because it’s not time-gated. I tell no lies!
If the patch notes didn’t specifically say that the Anniversary Event would happen in November, then you could argue it’s being time-gated. But they told us when it’s happening. The fact that they included the data in yesterday’s patch, as opposed to having another patch day (with its inevitable problems) mid November is just being efficient.
Like I said, the lunar festival holiday update was also included in yesterday’s patch – doesn’t mean the lunar festival is time-gated, because that stuff happens in February.