How does Acrobat Reader determine signature/timestamp hash algorithm?

Hi,

I have signed PDF. It contains signature and DocTimeStamp.

It should be signed using RSA SHA256.

When I open it in Acrobat Reader DC (v 15.023.20070) and display the Advanced Signature Properties, Hash algorithm is SHA1.

When I open it in Acrobat X Pro, the document hash algorithm is correctly set to SHA256.

When I use some ASN.1 tool (for example https://lapo.it/asn1js/ ) to display the SignedData, I see correctly SHA256 as the digest algorithm OID used.

Why is Acrobat Reader DC showing that the hash algorithm is SHA1?

Thank you.

Best regards,

Jakub