If:

• you have your search domains set to x, y;
• you have connectivity on both of IPv[46];
• a.x only has an A record; and,
• a.y has both A and AAAA,

then ssh a — 100% reliably for me, YMMV — will try connecting to a.y over v6 first!

This has had me confused for days, having recently reëstablished v6 in the home.

(Concretely: search domains are meshnet, public; vps.meshnet only has an A record, vps.public has A + AAAA. The VPS only listens to SSH on the meshnet. Up until now, ssh vps always went via the mesh, but since getting v6 up at home, it’s always trying the public address via v6 first and so hanging. It does actually time out and then try the meshnet address, so I guess it’s resolving all the candidates itself.. which makes sense, SSH takes care around address/IP mappings wrt. known hosts etc. The easiest solution for me has been to just add the v6 mesh address to DNS!)