PADES-LTV Document timestamp verification error

I am signing a pdf document in PADES-LTV signature format with a Document timestamp signature.

Usually, signed files are OK. Both signature and document timestamp signature is verified and everything is OK. However, s开发者_运维百科ometimes the following result occurs:

When I try to open the signed document with Adobe reader version 10.1.0.534, signature is validated however Document timestamp signature can not be verified. It says: At least one signature requires validating on the top bar. When I look at the Signatures section on the left, It says: Signer's identity is invalid because it has expired or is not yet valid. If I try to open the signature details of the document timestamp, Adobe reader crashes. (I submitted a bug report for this issue but I have not received any response yet)

When I open the signed document with Adobe Acrobat X pro and view the details of the document timestamp signature, this value "1970/01/01 03:00:00 +03'00'" is displayed in the signature date field. Actually, Date field should be Not available since ETSI 102 778-4 V1.1.2 says: In the document timestamp dictionary Name, M, Location, Reason and contact info should not be present.

Why does the adobe reader shows this value 1970/01/01 03:00:00 +03'00' instead of Not Available?

What can be wrong?

Thanks