Just from curiosity....

You see this behavior because your traceroute program does not
understand the ICMP "administratively prohibited" (ICMP type 3, code
13 - defined in RFC 1812) messages being sent back to it from

Cisco routers typically return ICMP messages of this nature to the
source of traffic which is being blocked by a traffic-filtering
ACL on the Cisco router.

                                - roy -