I had two 1.1.8 vyos routers on both ends of an OpenVPN site-to-site link. I upgraded the one end to 1.2.0-rolling, and the 1.1.8 stopped populating routes it received from the 1.2.0 end via OSPF. The 1.2.0 still accepted and used routes received from 1.1.8 via ospf. Weird.
So I changed device-type to tap, and now of course OSPF routes propagate in both directions.