Your netmask, /68, is that a typo?
Because I think that /64 is the smallest size you can advertise via routing protocols.
I'm also not sure what happens when you use private V6 networks (the ones starting with fd) and put them in BGP. Part of me says it should work, but I've never tried it. Just like I've never tried putting "192.168.1.0" into BGP.
Frank