QueryExecution create(Query query, Model model) return no result with named model

[AlexTo]

I'm having strange behaviour with QueryExecution create(Query query, Model model)

I created a named model and add triples to it as follows

Dataset ds = dg.toDataset();
ds.addNamedModel("urn:x-arq:LearningRecord", ModelFactory.createDefaultModel());
Model model = ds.getNamedModel("urn:x-arq:LearningRecord");
\\ read triples into model

Now, using Mark Logic query console, I can confirm that urn:x-arq:LearningRecord has been created with triples in it.
But now if I query with QueryExecutionFactory like this

QueryExecution qexec = QueryExecutionFactory.create(query, dg.toDataset().getNamedModel("urn:x-arq:LearningRecord"));
ResultSet resultSet = qexec.execSelect();

then resultSet.hasNext() is false
But if I query without getNamedModel like this

QueryExecution qexec = QueryExecutionFactory.create(query, dg.toDataset());
ResultSet resultSet = qexec.execSelect();

then I can retrieve expected results. From IntelliJ debugger, I can also see that urn:x-arq:LearningRecord is part of the DatasetGraph

Is it possible to query triples in a specific named model? seems like the query will return triples from the union of all models.

FYI, Jena or Virtuoso doesn't have such issue.

Thanks