PGP Signature and Email Text Signature not Working

I’m using a signature block on all my e-mails, and with the addition of PGP, I wanted to start digitally signing my emails. However, when I write an e-mail using my text signature block inside the message, the receiver sees the message as a bad PGP signature. Specifically, the message hash differs from the signature value. Has anyone else had this issue, and how has it been resolved? If I remove the text signature block, the PGP signature works fine… Thanks all!

I seem to have this same issue with message replies only; not when I attached a text or HTML signature to outbound emails.