3.2 Multicast Basics Issue
A task needs to be added to create an ipv6 address for R6's vlan 46 interface to be 2001:CC1E:X:404::/64 eui-64. I was unable to get R5 to successfully ping FF06::6 without this.
After looking at the debug ipv6 icmp for R6 was src its echo-reply from it's link-local address. And R4 would then send dest unreachable back to R6.
See below from R6 debug:
ICMPv6: Received echo request, Src=2001:CC1E:27:4545::5, Dst=FF06::6
ICMPv6: Sent echo reply, Src=FE80::219:56FF:FED4:F922, Dst=2001:CC1E:27:4545::5
ICMPv6: Received Unreachable code 2, Src=FE80::21A:6CFF:FE6B:D39B, Dst=FE80::219:56FF:FED4:F922