Once the new graph feature install, try to create a graph with some vertices, edges and prefix in the datastore through restconf/config/graph:graph-topology result to an empty connected graph: the connected graph is created, but not the connected Vertex, connected Edges and connected Prefix.

A possible workaround is to decouple the creation of the graph and its fulfillment. First, create an empty graph without vertices, edges and prefix and then update it with list of vertices, edges and prefix. This time, the connected graph is correctly created and fulfill.