Outlook Addin Event handler clean up - event-handling

Question

I am having problems with the event handler in my office addin . Below is an example code i got from microsoft website to explain what i mean.
I have a manifest file that uses the on-send hook as well as a click-based event triggering.
My button calls appendMessageBodyOnClick and onsend i call appendMessageBodyOnSend. Both function primarily do the same thing. I never want to block sending emails regardless.
The problem is that the event object is not properly cleaned up i think.
Scenario 1
When i click my button ; which calls event.completed(), and then after i try to send the message, it says my app is blocking the message, but then when i try to send again it goes through.
Scenario 2
When i leave the subject empty and then send the message, as expected i am prompted that the subject is empty. If i cancel sending the message on this note and then click on my button, the message tries to send as though i clicked send.
I am supposing the is some sort or state clean up issue. What am i doing wrong here?
Function-File.js
function appendMessageBodyOnClick(event) {
// Append string to message body
event.completed();
}
// In the following example, the checkMessage function has
// been registered as an event handler for ItemSend.
function appendMessageBodyOnSend(event) {
// Append string to message body
event.completed({allowEvent = true});
}

Answer 1

Not sure if this will help, but I also have faced some seemingly inconsistent behavior while understanding how to signal that event is fully completed. Once I got my edge cases fixed, then it worked.
One suggestion: Appending string to message body should be an async function. Call the event.completed() from inside the callback function. (i.e: make sure when you are calling event.completed(), nothing else is pending -like another async result)
Something like the following:
Office.context.mailbox.item.body.setAsync("new body", function(asyncResult) {
// handle success and failure
event.completed()
});
Same would be for your scenario 2, make sure event.completed() is called at the very end.