Tailscale version 1.38.4 on the remote and local host
Your operating system & version: local host is Debian Bullseye, Remote is Ubuntu 18.04
I have tailscale ssh set up with the right ACLs. I can do a tailscale ssh to the remote host and I am not prompted to accept the remote host key as expected. However, If I use ssh ... instead of tailscale ssh the first time I connect I am prompted to accept the host key (“The authenticity of host … can’t be established.”) though clearly the tailscale is controlling the ssh connection as I am not prompted for a login password. I thought one of the benefits of tailscale ssh was not having to authenticate the remote host.
Note that one use case here is to bulk provision a bunch of IoT devices via Ansible so accepting all the host keys would be problematic.