Previous step shouldn't check (validate) current form

Not validating a form is not a good idea (data corruption, security, etc.). The only way around that is to not actually submit the form, but the Previous button is a submit button. The reason why I'm marking this as won't fix is because, first, not submitting the form means that the user will lose the information they have entered in that step; and lastly, there is already a navigation menu, provided as a block, which allows the user to jump between steps.

I also think this should only check the form if user has changed the data, other than that users tend to use this button to go back to the previous page and they face an error, I also like to have this feature