Create signature field programatically

When I manually add a signature field I can sign immediately without saving, closing, and re-opening the PDF.  When I add a signature field programatically I can sign immediately without saving, closing, and re-opening the PDF. However, when I add a signature field programatically and also add a script to the field to be executed after signing (it doesn't matter what the script is) I get an error message: "This document could not be signed in it's current state.  Please save the document, close it, reopen it, and attempt to sign it again."  Doing what the message says works but I don't want to have to do that.  I have same issue in Acrobat Pro X  and Acrobat Pro DC.  Does any one know this happens and if there is a way around it?