I upgraded my LAN to IPv6 and have run into a problem with OTBR. The BR does not appear to be advertising itself as a router on the LAN. I don't see anything regarding this in the documentation, so I'm not certain what I'm missing here.
Using tcpdump, I've traced a ping from the OpenThread network, through the OTBR, to the destination machine. The tcpdump from the destination machine shows the destination machine sending the reply to the fd11:22:: OpenThread address, but there is no sign of that reply in the OTBR's tcpdump logs.
Checking the destination machine's routing table shows no sign of the fd11:22:: OpenThread network. However, if I manually insert a route to the fd11:22:: network, via the OTBR, the pings will now work.
So, in summary, I seem to be missing something regarding having the OTBR advertise itself as a router.