Previous button behavior like submit button

See #3401338-10: Several errors and warnings in the console → : this is due to the module's invalid approach of trying to make the Stripe payment request whilst building up the AJAX request to submit the form back or forward. We've got a merge request there with a fix that should fix this problem too as it moves away from overriding any standard AJAX behaviour :) Please can you try the fix out to see if it solves your problem? Thanks!