Hi Gilles,
When you navigate back to main page, can you try placing this code in onAfterRendering event of main controller and check whether your model still exists with data ?
onAfterRendering: function(oEvent){
sap.ui.getCore().getModel("Appconf").getProperty("/results");
//(or)
this.getView().getModel("Appconf").getProperty("/results");
}Regards,
Sai Vellanki.