just an update on this issue.
Standard browsers do not allow file field to retain persistent data. Ok, I can understand.
So, going back to previous page and re-submitting the same form (with a file field) would produce errors for required file field. This is ok and I'm fine with it.
But now chrome behaves in another way: if you go back to the form page and re-submit the page without re-selecting any file, it will not throw any error and the form is submitted.
This happens only with Chrome (v.63 or v.64). Firefox and Edge work as expected.
What can I do to make the form work consistently across all browser?
Actually I checked the REQUIRED checkbox for the file fields and it seems to stop chrome to submit if no file is selected.
Perhaps Chrome is the new IE6?
Thanks in advance for any help.