There may be more unfermentables, but assuming you used the same amount of DME, you didn't get any sugars out of the crystal because the OG didn't change. Therefore, you would have the same amount of sugars in each batch. OG and FG are measurements of sugar. So if the total amount of sugar didn't change, the only thing that changed was that the yeast didn't consume as much sugar in the second batch as the first batch. Now, had you reduced the DME and obtained some sugars from the Crystal, then I would probably agree with you because some of the sugars obtained from the Crystal were not fermentable.