Acrobat is not updating the AATL trust list automatically or even asking when a document that is signed is opened.

There is a checkbox under Preferences > General > Trust Manager > The Automatic Adobe Approved Trust List (AATL) updates. Load trusted certificates from an Adobe AATL Server is checked. This is the default when you install acrobat. It however does not update the list. If you uncheck the box, close Acrobat, then open Acrobat check and reclose and open, it works.

Most users won't know to go here and all documents end up looking like they are not valid.

I would like to submit this bug.

I have seen many posts instructing users to add the certificate manually to the trusted certificates which is a bad idea. Updating the AATL solves this issue for all certificates that are signed using AATL partners.