It is not possible to directly access nodes under "vrf-subtable". For example configuring adjacency:

1. create vrf-subtable with table-id
PUT /restconf/config/lisp:lisp/lisp-feature-data/eid-table/vni-table
{"vni-table": [{"vrf-subtable": {
"virtual-network-identifier": 4,
"local-mappings":

{"eid":...}

,
"remote-mappings":

{"eid":..., "id":"remote_map_vrf"}

,
"table-id":1}]}

2. add adjacency to existing vrf-subtable
PUT /restconf/config/lisp:lisp/lisp-feature-data/eid-table/vni-table/4/vrf-subtable/remote-mappings/remote-mapping/remote_map_vrf/adjacencies/adjacency/adj01
{"adjacency":

{ "id": "adj01", "local-eid":..., "remote-eid":...}

will result in Error 500: node "vrf-subtable" is missing mandatory descendant "table-id"

But "table-id" is already stored in configuration for the "vrf-subtable" parent, and this PUT operation does not attempt to modify it.