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This is correct. You receive Gold status, but you do not receive any Nights for credit toward renewal or toward a higher status level. Next year you will again receive Gold status, provided that you still hold an American Express Platinum card -and- assuming that Amex and Marriott renew this agreement.
thank you very much for the very quick reply! this threw me off because my hilton honors app clearly states that i need 0 nights to maintain gold status. while on the marriott app it says 20 nights (I did 5 this year). so I was afraid that next year I will be downgraded because of this bug. instead you confirmed that it is normal to see "you need 25 nights to mantain the gold"