According to the information provided in the FAQs section of the Certified in Cybersecurity℠ - CC certification webpage (https://www.isc2.org/Certifications/CC), it says :
I have already paid my Associate of ISC2 $50 AMF for the year, but now when I go to the Maintence Fee tab and the dashboard, I see that $75 is the new AMF fee. Please fix this since according to the FAQ it states: "Those who pass the Certified in Cybersecurity exam who have already paid their AMF for either the Candidate or Associate role will not need to pay any additional annual dues or AMF fees to be a fully Certified in Cybersecurity member."
Yep, same here. I've had seemingly the exact same experience as you then... @andrew2