Thank you all for responding. I was confused as to why the issuer of the 1099-R entered 0 as the taxable amount (as I was sure that was incorrect)....and also indicated the taxable amount was unknown. I still am. 

The taxpayer researched and previous years listed the same amount in gross distribution and taxable amount with the unknown box checked. I am not sure why the procedure changed but can only guess a new third party is issuing the 1099-Rs.