A question about the property service, on the saved event.

if i use the onsaving event:

void ContentService_Saving(IContentService sender, SaveEventArgs<IContent> e)
{
    foreach (IContent node in e.SavedEntities)
    {
    if(node.IsPropertyDirty("property name"))
    {
        //Do something
    }
}       

}

When i edit the property it is true and the code would work as i expect.

However if i do the same thing on the saved event and use was property dirty, it will always return true even if i have not edited the property in the CMS.

void ContentService_Saved(IContentService sender, SaveEventArgs<IContent> e)
{
    foreach (IContent node in e.SavedEntities)
    {
        if(node.WasPropertyDirty("property name"))
        {
            //Do something
        }
    }       

}

Am i missing something here why would a property be marked dirty if it hasn't been changed?