tested on trusty:
using isc-dhcp-client 4.2.4-7ubuntu12.6, bug exists; dhcpv6 prefix is set to /64.
using isc-dhcp-client 4.2.4-7ubuntu12.7, bug is fixed; dhcpv6 prefix is set correctly to /128.
tested on trusty:
using isc-dhcp-client 4.2.4-7ubuntu12.6, bug exists; dhcpv6 prefix is set to /64.
using isc-dhcp-client 4.2.4-7ubuntu12.7, bug is fixed; dhcpv6 prefix is set correctly to /128.