I've had problems running OSPF over my WiFi network, and it seems to be related to multicast. The routers can't maintain a neighbor relationship, and when I watch the packet traffic I see one router sending multicast Hellos to 184.108.40.206 but the other OSPF speaker is not receiving them.
The OSPF speakers are all Ubuntu Linux machines (either Ubuntu 18 or 20) running Quagga. The AP is a Verizon Fios G1100.
I'm pretty sure there's a bug somewhere, but I'm not sure where. Since there's no true broadcast or multicast over WiFi, the AP has to relay the multicast frames. Should it do this automatically? Or should the OSPF speakers announce their interest in 220.127.116.11 via IGMP?
Incidentally, adding a neighbor statement to the Quagga configuration doesn't seem to help. I resolved the problem by switching to RIP.