Can't view Digital Signature-Acrobat Pro DC (Windows)

Hi -

I had a trading partner send me a document which they had digitally signed.  When I open the document in Acrobat Pro DC (v.2018.011.20035 - Windows), the signature is not present.  In fact, the signature box is in the document asking for ME to sign.

The sender has sent me screen shots showing the signature on their end.  We have even had them open the document after I returned it to them, and the signature is still present for them.

Finally, I CAN see the signature if I use the attachment preview feature in Outlook 2016.  Is there some setting in Acrobat Pro which might help here ?

thanks... Dwight