The behavior is shown via the command show ospfv3 lsdb detail lstype as-external. It shows the correct Advertising Router and Forwarding Address that should be learned.
"show ospfv3 lsdb detail lstype as-external"
AS External LSA
LS Age: 20
LS Type: AS-external-LSA
Link State ID: 0.0.0.1
Advertising Router: 184.108.40.206
LS Sequence Number: 0x800000ed
Metric Type: 2
Prefix Options: 0x0 (-|-|-|-)
Forwarding Address: 2001:12f0:0:fd::6d
Then when we perform the iproute command, we see no entry.
#:sh iproute ipv6 ::/0
Ori Destination Mtr Flags Duration Gateway Interface
No entry is found.