Security defaults will be enabled automatically for your organization - ADFS with DUO MFA - why am I getting this prompt in 365?

Why am I getting this ? 365 is forcing some of our tenants to turn on security defaults.
We have ADFS with DUO 2fa. Does Microsoft not know we have DUO as 2fa? what should be the next step?

365 would not know that a federated IdP, like AD FS, would itself have some plugin installed that adds MFA.

However, you can configure AD FS such that when someone does complete Duo MFA via the installed plugin the info AD FS sends back to 365/Azure includes the information that a user completed MFA at AD FS.

Find those instructions here: Pass an MFA Claim to Microsoft.