Prepare Form: AcroForm Signature Field saved/rendered as Text field

Since circa a month, I cannot add a Signature Field in Prepare Form Acrobat DC functionality.

I'm using the "Add Signature Field" toolbar button.

The field properties dialog shows me the right Signature type.

If I save the document and I open it with Fill and Sign Acrobat DC functionality, the signature field is rendered as a text file.

Also using other external tools the field is recognised as text field.

Inspecting PDF file at lower level, in the PDF AcroForm catalogue, the field has the /FT field with "Tx" value, that following PDF specifications it is a text field (Signature fields must have the value "Sig").

I'm pretty sure this problem was introduced with a recent update because a month ago (with version 2015.017.20053) the functionality was working.

BTW: the Add Signature toolbar button is changed, in the new version there are 2 add signature button: Add Signature Field and Add Signature Block...

Anyone experienced the same behaviour?

How can I workaround too restore previous functionality?

Thanks.

Message was edited by: Davide Ramo