I have a fairly standard profile editing page (password, email, etc.) that contains one standard file input element. Since the file input field is the last editable field in the form, the submit button is directly afterwards. There's not a single form on the website that submits/saves automatically. The feedback I've received from management is that it is "confusing" and they've requested adding a note telling the user that the form has to be submitted or the file won't be uploaded.
There is another page on the website that deals with uploading multiple images that also does not automatically submit, but does not appear to have the same confusion (it also has a single standard file input element in addition to being JS enhanced with image previews, progress bars, etc).
Are users genuinely confused by how the file input element works?
Update (because everyone seems confused by the spirit of the question): I'm not really interested in how I can improve my form, but whether or not users are confused by how forms with a file input element work. If they are confused, what causes the confusion? The UX of this particular project has been run-over by management for months now and I'm convinced they're underestimating the average user's intelligence in this particular instance. Because the project has not launched yet, there are no real users using it so I have no data to show how they actually behave to back-up my gut.