Hello,
I had the same issue, only with readonly fields or value fields.
For readonly fields, it’s due to the “disabled” attribut added to <input> htlm tag. By using “readonly” attribut instead “disabled”, your field is transfered into the cart page.
For text fields for exemple, see \classes\fields\wcff-text.php l. 276 and replace
//$readonly = ( $readonly == “yes” ) ? “disabled” : “”;
$readonly = ( $readonly == “yes” ) ? “readonly” : “”;
For having readonly look for your field, just modify styles.css.
