nested model associations cleared after initial load?

[nds9619]

I've created a custom proxy type for retrieving data from a javascript remoting method that returns an array of objects. The issue is that during autoLoad, the ListStore shows values in the "Contacts" array. However, once I click on a List component bound to this store, the Contacts array for each record is cleared. I suspect is has something to do with

        read: function (operation, callback, scope) {             //Here goes your read logic
            HTML5RemoteExtensions.query('Select ID,Name,Type,AccountNumber,Industry,AnnualRevenue,Phone, (Select Id, Name from Contacts) from Account',function handleResponse (result, event) {  //, (Select Id, Name from Contacts)
                console.log(JSON.stringify(result));                
                demos.ListStore.loadData(result.records);
                demos.ListStore.sort('Name', 'ASC');
                demos.ListStore.loading = false;              
                demos.ListStore.sync();
            }, {escape:false}
            );     
        },

And the Model:

Ext.regModel('Account', {    fields: ['Id', 'Name', 'Type', 'AccountNumber', 'Industry', 'AnnualRevenue', 'Phone', 'Contacts'], 
    associations:[
        {type: 'hasMany', model: 'Contact', name: 'Contacts'}
    ],    
    idProperty: 'Id',         
    proxy: {
        type: 'myProxy',
        reader: {
            type: 'json',
            totalProperty: 'totalSize',
            successProperty: 'done',
            root: 'records'
        }  
   } 
});
Ext.regModel('Contact', {
    fields: ['Id', 'Name', 'AccountId'],  
    belongsTo: ['Account', {model: 'Account', associationKey: 'AccountId'}],
    idProperty:'Id'
});

And the data returned from initial "read":

{"records":[{"Name":"test5","RecordTypeId":"012U0000000KLkCIAW","Type":"first","Id":"001U00000071eXtIAI","Industry":"first"},{"Name":"GenePoint","Phone":"(650) 867-3450","AccountNumber":"CC978213","Type":"second","Contacts":[{"Name":"Edna Frank","AccountId":"001U0000002KPCDIA4","Id":"003U0000001XpgCIAS"}],"Id":"001U0000002KPCDIA4","AnnualRevenue":30000000,"Industry":"Biotechnology"}]}

And the debug of the ListStore after rendering the list component:

{"Name":"GenePoint","Phone":"(650) 867-3450","AccountNumber":"CC978213","Type":"second","Contacts":[],"Id":"001U0000002KPCDIA4","AnnualRevenue":30000000,"Industry":"Biotechnology"}