CAC Certificates not recognized after Mac OS patch 24 Sep 2020

If this is happening in government computers try to get support first through your IT support team; see if they know of any issues with that patch.

If this is a personal computer check with the Apple support forums and any release notes related to that patch.

As far as Acrobat, I would say to create a new user profile account in that computer and test if the same problem manifests with a new user account.

If the same problem occurs with new account, then try to see if the problem is corrected by uninstalling and reinstalling  Acrobat, or,

Verify if revocation, the trust information, the expiration date, or the certificate's store location changed.

You may need to  view the information stored for that certificate in the keychain, and specifically the information that belongs to your signing certificate in Acrobat.

Follow this Apple support guidance for your OS to view information in the keychain : 

https://support.apple.com/guide/keychain-access/view-the-information-stored-in-a-keychain-kyca1085/10.5/mac/10.14

You may have to review the keychain information for that  certificate and see if its trust and validity was lost after the patch was applied.

In Acrobat, you can also go to Edit--->>>Preferences--->>>Signatures--->>> "Identities & Trusted Certificates", click on "More". You should be able to open the certificate manager by clicking on the  "Digital iDs" link and also  be able to edit the trust by clicking on the "Trusted Certificates" link.

Don't forget to check all other preference settings in  the "Signature" section, not just the certificates.