MAGETWO-90970: State field becomes required after page refresh during checkout

Author: rganin

app/code/Magento/Ui/view/base/web/js/form/element/region.js

@@ -49,6 +49,10 @@ define([
                 if (option && !option['is_region_required']) {
                     this.error(false);
                     this.validation = _.omit(this.validation, 'required-entry');
+                    registry.get(this.customName, function (input) {
+                        input.validation['required-entry'] = false;
+                        input.required(false);
+                    });
                 } else {
                     this.validation['required-entry'] = true;
                 }