Why is Adobe Sign automatically adding signature fields?

I’m unable to reproduce the problem today. I’ve been using the same process to prepare Excel project workbooks for signature for close to a decade without this issue, so maybe it was just a temporary glitch with the way the Excel Adobe plugin was converting the workbook before loading into AdobeSign. Basically, AdobeSign was automatically converting every empty cell in the PDF into a signature field. I tried multiple workbooks over the span of several hours yesterday, finally resorting to manually deleting each signature field. But they seem to be uploading to Adobe Sign just fine today, it’s back to letting me add the signature fields manually. If the problem comes back I’ll upload a copy of the document.