IdenTrust Global Common Root is not in the Trusted Certificate List

I am signing documents using a certificate issued by Identrust under the IdenTrust Global Common Root.  I have had clients open my documents and receive a “signer invalid” error.

IdenTrust Global Common Root  is part of the AATL so I assumed that the CA cert would be auto added to the trusted certificates list, but currently the only work around is to manually add and trust the identrust global common cert.  I did not used to have this issue; is there a reason this cert was remove from the trusted list?