Just noticed this in my Amex account today (Platinum Edge). I didn’t get an email. Check your accounts for details

This will be a targeted offer, but good for those who get it when all regular spend over multiple transactions are included. It will NOT be applicable to Bank issued Amex cards (eg Amex Amex only).

“MEMBERSHIP REWARDS
Spend $1,600 or more, get 3,000 MR points
Save offer to eligible Card, spend $1,600 or more, in one or more transactions, online, in-app or in-store at American Express accepting merchants from 08/11/2017 to 07/12/2017 to get 3,000 MR Bonus Points. Limited to 9,000 Cards. Exclusions apply. Please read the Offer Terms”

Also note an additional term re supp card spends:
“Offer applies to eligible spend on the registered Card and attached supplementary cards only. Offer does not apply to spend on other Cards you might hold.”