When you get divorced or a civil partnership is dissolved, the Court takes the value of your pension into account in any settlement. If your pension includes an underpin amount, then that increase is included and, if your pension is shared, part of that increase will be passed to your former spouse or civil partner.
For most members the pension they built up in the career average scheme is higher than they would have built up in the final salary scheme, so no underpin applies and there is no change to the pension share awarded to their former spouse or civil partner.