I just noticed that the name of the hotel has changed. I don't know how long it's been.
What had been
AC Hotel Palacio De Santa Paula, Autograph Collection is now simply
Hotel Palacio De Santa Paula, Autograph Collection on Marriott.com.
Let's hope this reduces the confusion about whether it provides Rewards benefits under the rules of AC Hotels or Autograph Collection.
AC Hotels, named after founder Antonio Catalán, became part of Marriott in 2011. Most of those hotels became part of a new brand for Marriott. A handful of higher-end properties became part of Autograph Collection, but retained their old "AC" names -- as if it wasn't confusing enough that AC was often incorrectly perceived as an abbreviation for Autograph Collection.
Perhaps someone could remove "AC" from the topic name of this FlyerTalk thread.