https://github.com/magento/magento2/commit/ecda90b87ef2bee51a5a003d459647ffe0b49e32

diff --git a/vendor/magento/module-checkout/view/frontend/web/js/action/update-shopping-cart.js b/vendor/magento/module-checkout/view/frontend/web/js/action/update-shopping-cart.js
index 48e79f1d00833..0d4faed0c7384 100644
--- a/vendor/magento/module-checkout/view/frontend/web/js/action/update-shopping-cart.js
+++ b/vendor/magento/module-checkout/view/frontend/web/js/action/update-shopping-cart.js
@@ -154,7 +154,12 @@ define([
         onError: function (response) {
             var that = this,
                 elm,
+                responseData = [];
+
+            try {
                 responseData = JSON.parse(response['error_message']);
+            } catch (error) {
+            }

             if (response['error_message']) {
                 try {