OBA will never return data from a graph.

[DougalW]

When testing OBA on the DBPedia Music example, and creating local API servers, OBA will never return data from a Graph.

Our testing suggests that the framed @context variable is not populated with the result set returned from a triple store, and so when it is processed by PyLD, it drops the graph result set and hence never returns data to the calling web page.

[dgarijo]

The context should be populated with the input ontology, and it should be the same for all queries. Basically, the returned data changes but the context remains the same. That's why OBA would be slower if the ontology used was huge.
Are you sure the context is saved correctly? Other than that, we checked this example and had it with Docker in our early releases. I have not checked if after the latest changes from @mosoriob to OBASparql, the example is still ok. We should have some tests to double check that.