IPv6 Route List entry unreachable

I have a problem on a x86 system with 4.2 and can’t find any solution.

If I add an IPv6 address (/64) the dynamic IPv6 entry of the IPv6 route list writes gateway unreachable if I bind it to any VLAN of GE3 (in my config the LAN Interface).

If I change the ipv6 address to a VLAN on a different network interface (GE4) the gateway is reachable.

All VLAN’s working without any problems with IPv4.

Thanks for any hints.

Raimund Zalaudek