show registration sipd by-ip command

I need assistance to understand why the show registration sipd by-ip

command is not providing any registrations when entering the complete IP address.

Below is the output for when entering the entire IP adress with no registration

entries vs when enetring the IP partually.

TPPR_SBC_AC_02> show registration sipd by-ip 192.168.8.207

Registration Cache                    Wed Mar 13 2019  08:46:05

                                                   Num

  IP Address      User                             Contacts Registered at

----------------- -------------------------------- -------- -------------------

No matching entries found!

TPPR_SBC_AC_02> show registration sipd by-ip 192.168.8.  

Registration Cache                    Wed Mar 13 2019  08:46:09

                                                   Num

  IP Address      User                             Contacts Registered at

----------------- -------------------------------- -------- -------------------

  192.168.8.144   sip:27211162011@192.168.252.131   1        2019-03-05-14:57:51

  192.168.8.144   sip:27112771653@192.168.252.128   1        2019-03-10-13:44:09