Multipage submitted form will not save changes when moving from page to page

We have a multipage webform that gets re-edited every year.

When a user creates a new submission a draft is saved every time he moves from page to page and his work on the form is thus saved.
When a user goes in to edit a submission that has already been submitted via the last page button, then the editing that he does is only retained if he reaches the last page and presses the submit button.

I understand there are reasons to consider this normal behaviour but it is a problem in our case.
Plus I believe this behaviour has changed in the last year. I do not remember testing it myself but it has been reported by users as a new bug causing them to loose their work.

Is there anything we can do here?
Like adding a "Save" button in every page when re-editing submitted forms?