The Merge Data Files into Spreadsheet feature works great until the form has a signature added to it. After the form is signed only a few of the fields are exported. It's as if the data elements have been truncated.

To replicate... create a form with many data fields (populated) and a signature field but without requesting a signature. Do the Merge Data Files into Spreadsheet... it works great.

Repeat the Merge Data Files into Spreadsheet function but this time after requesting a signature. This time the spreadsheet created has minimal data.