Unable to fetch built in properties of email along with the extended property using EWS Managed API

I am working with Exchange Web Services Managed API. I am adding a single extended property to mail items in inbox as they get processed based on some condition. Thus, not all mails will get this extended property attached to them.

Next I am refetching all mails in inbox and if they have this property attached to them, I process them again.

Below is the simple method getAllMailsInInbox(), I have written to refetch the mails in inbox:

classMyClass{privatestaticGuid isProcessedPropertySetId;privatestaticExtendedPropertyDefinition isProcessedPropertyDefinition =null;staticMyClass(){
        isProcessedPropertySetId =newGuid("{20F3C09F-7CAD-44c6-BDBF-8FCB324244}");
        isProcessedPropertyDefinition =newExtendedPropertyDefinition(isProcessedPropertySetId,"IsItemProcessed",MapiPropertyType.String);}publicList<EmailMessage> getAllMailsInInbox(){List<EmailMessage> emails =newList<EmailMessage>();ItemView itemView =newItemView(100,0);FindItemsResults<Item> itemResults =null;PropertySet psPropSet =newPropertySet(BasePropertySet.IdOnly);
        itemView.PropertySet= psPropSet;PropertySet itItemPropSet =newPropertySet(BasePropertySet.IdOnly,ItemSchema.Attachments,ItemSchema.Subject,ItemSchema.Importance,ItemSchema.DateTimeReceived,ItemSchema.DateTimeSent,ItemSchema.ItemClass,ItemSchema.Size,ItemSchema.Sensitivity,EmailMessageSchema.From,EmailMessageSchema.CcRecipients,EmailMessageSchema.ToRecipients,EmailMessageSchema.InternetMessageId,ItemSchema.MimeContent,
                                          isProcessedPropertyDefinition);//***

         itemResults = service.FindItems(WellKnownFolderName.Inbox, itemView);
         service.LoadPropertiesForItems(itemResults.Items, itItemPropSet);String subject = itItem.Subject;//Exception: "You must load or assign this property before you can read its value."//....}}

As you can see, on call service.LoadPropertiesForItems(), it does not load any properties, thus resulting in You must load or assign this property before you can read its value.exception while accessing any of those properties.

If I remove isProcessedPropertyDefinition from the itItemPropSet property set, it fetches all the properties properly.

So can I just know how can I fetch all built in EmailMessage properties along with the extended property?