>Compute Transport Node, I configure the default-gateway but don't remember anywhere I could configure any Vlan tagging
I was able to use the uplink profile to apply a vlan tag. The default uplink profiles do not provide a vlan tag. I copied the nsx-default-uplink-hostswitch-profile, included a tag for my tep vlan, then applied the new custom uplink-profile in my Transport Node Profile.
I was experiencing a similar issue with a failed Geneve tunnel. My edges established a tunnel just fine (edge to edge) so i was confident mtu, vlan tag and trunk was correct. My transport nodes would not establish to each other - nor the edges until i Tagged the vlan via the uplink profile.