If you use IdentitiesOnly yes
in your SSH config, because you want to limit the key
info you send to random SSH servers, it may not work for some teleport+ssh services like for git.domain.com
One alternative is to have:
Host git.domain.com
ProxyCommand ssh -A -p 3023 %r@teleport.domain.com -s proxy:%h:22
IdentitiesOnly no
Host teleport.domain.com
IdentitiesOnly no
Host other.host
IdentityFile /path/to/identity
Host *
IdentitiesOnly yes