diff -u b/core/modules/file/file.es6.js b/core/modules/file/file.es6.js
--- b/core/modules/file/file.es6.js
+++ b/core/modules/file/file.es6.js
@@ -85,13 +85,13 @@
   Drupal.behaviors.fileButtons = {
     attach(context) {
       const $context = $(context);
-      $context.find('.js-form-submit').on('replaceProgressBar.fileButtons', Drupal.file.disableFields);
-      $context.find('.js-form-managed-file .js-form-submit').on('replaceProgressBar.fileButtons', Drupal.file.progressBar);
+      $context.find('.js-form-submit').on('mousedown', Drupal.file.disableFields);
+      $context.find('.js-form-managed-file .js-form-submit').on('mousedown', Drupal.file.progressBar);
     },
     detach(context) {
       const $context = $(context);
-      $context.find('.js-form-submit').off('replaceProgressBar.fileButtons');
-      $context.find('.js-form-managed-file .js-form-submit').off('replaceProgressBar.fileButtons');
+      $context.find('.js-form-submit').off('mousedown', Drupal.file.disableFields);
+      $context.find('.js-form-managed-file .js-form-submit').off('mousedown', Drupal.file.progressBar);
     },
   };
 
@@ -167,11 +167,8 @@
      *   The event triggered. For example `change.autoFileUpload`.
      */
     triggerUploadButton(event) {
-      $(event.target).closest('.js-form-managed-file').find('.js-form-submit')
-        // Setup required elements for progress bar.
-        .trigger('replaceProgressBar')
-        // Trigger ajax submission.
-        .trigger('mousedown');
+      Drupal.file.progressBar(event);
+      $(event.target).closest('.js-form-managed-file').find('.js-form-submit').trigger('mousedown');
     },
 
     /**
@@ -221,7 +218,7 @@
      *   The event triggered, most likely a `mousedown` event.
      */
     progressBar(event) {
-      const $clickedButton = $(this);
+      const $clickedButton = $(event.target).closest('.js-form-managed-file').find('.js-form-submit');
       const $progressId = $clickedButton.closest('div.js-form-managed-file').find('input.file-progress');
       if ($progressId.length) {
         const originalName = $progressId.attr('name');
diff -u b/core/modules/file/file.js b/core/modules/file/file.js
--- b/core/modules/file/file.js
+++ b/core/modules/file/file.js
@@ -49,13 +49,13 @@
   Drupal.behaviors.fileButtons = {
     attach: function attach(context) {
       var $context = $(context);
-      $context.find('.js-form-submit').on('replaceProgressBar.fileButtons', Drupal.file.disableFields);
-      $context.find('.js-form-managed-file .js-form-submit').on('replaceProgressBar.fileButtons', Drupal.file.progressBar);
+      $context.find('.js-form-submit').on('mousedown', Drupal.file.disableFields);
+      $context.find('.js-form-managed-file .js-form-submit').on('mousedown', Drupal.file.progressBar);
     },
     detach: function detach(context) {
       var $context = $(context);
-      $context.find('.js-form-submit').off('replaceProgressBar.fileButtons');
-      $context.find('.js-form-managed-file .js-form-submit').off('replaceProgressBar.fileButtons');
+      $context.find('.js-form-submit').off('mousedown', Drupal.file.disableFields);
+      $context.find('.js-form-managed-file .js-form-submit').off('mousedown', Drupal.file.progressBar);
     }
   };
 
@@ -90,7 +90,8 @@
       }
     },
     triggerUploadButton: function triggerUploadButton(event) {
-      $(event.target).closest('.js-form-managed-file').find('.js-form-submit').trigger('replaceProgressBar').trigger('mousedown');
+      Drupal.file.progressBar(event);
+      $(event.target).closest('.js-form-managed-file').find('.js-form-submit').trigger('mousedown');
     },
     disableFields: function disableFields(event) {
       var $clickedButton = $(this).findOnce('ajax');
@@ -111,7 +112,7 @@
       }, 1000);
     },
     progressBar: function progressBar(event) {
-      var $clickedButton = $(this);
+      var $clickedButton = $(event.target).closest('.js-form-managed-file').find('.js-form-submit');
       var $progressId = $clickedButton.closest('div.js-form-managed-file').find('input.file-progress');
       if ($progressId.length) {
         var originalName = $progressId.attr('name');