The default route should go to <prefix>::1/64 as shown in the emails and on the configuration site in your user home. The only tunnels having 'problems' with the fact that linux suddenly implemented anycast addressing and nobody read the release notes are on the IPng POP. As these use a /127 from the time that such use was still normal and there where no standards about /64's per link. You might also want to check out this forum and especially the setup forum where you will find a number of 2.4.21 threads.