PersistenceNucleusContextImpl:getMultiTenancyReadIds line 1928 return new String[] {ec.getStringProperty(PropertyNames.PROPERTY_MAPPING_TENANT_ID)};

I receive this error because LocateRequest does this String[] tenantReadIds = storeMgr.getNucleusContext().getMultiTenancyReadIds(null);
The provided executionContext (ec) is null.

Context:
When I perform a find, it seems the tenant is not used. So I guess it could be related to caches. So I'm forcing DN to validate objects in the datastore using datanucleus.findObject.validateWhenCached=true at the EntityManagerFactory level.  

I attach a Junit Testcase. Just have a look at testInsertFind -> checkFind -> entityManager.find(Element.class, id)