The wppfm_cdata_keys() function makes it possible to add attributes to be included in CDATA bracket.

gistfile1.txt

function expand_cdata_attributes( $cdata_attributes ) {
  
  // price and availability attributes are added to the list of attributes that are included in a CDATA bracket
  array_push( $cdata_attributes, 'price', 'availability' );

  return $cdata_attributes;
}

add_filter( 'wppfm_cdata_keys', 'expand_cdata_attributes' );