diff --git a/core/modules/layout_builder/css/layout-builder.css b/core/modules/layout_builder/css/layout-builder.css
index 5ea3f503b3..3106c6b57c 100644
--- a/core/modules/layout_builder/css/layout-builder.css
+++ b/core/modules/layout_builder/css/layout-builder.css
@@ -75,13 +75,13 @@
   pointer-events: none;
 }
 
-.layout-builder-grid-mode .layout-builder-block {
+.layout-builder--grid-mode .layout-builder-block {
   border-bottom: 2px dashed #979797;
   cursor: move;
   margin: 0;
 }
 
-.layout-builder-grid-mode .layout-builder-block__grid-mode-label {
+.layout-builder--grid-mode .layout-builder-block__grid-mode-label {
   margin: 0;
   text-align: center;
 }
diff --git a/core/modules/layout_builder/js/layout-builder.es6.js b/core/modules/layout_builder/js/layout-builder.es6.js
index cd2d1d8b02..bae82e6277 100644
--- a/core/modules/layout_builder/js/layout-builder.es6.js
+++ b/core/modules/layout_builder/js/layout-builder.es6.js
@@ -220,12 +220,9 @@
        *
        * Grid mode hides block preview content. It is replaced with the value
        * of the block's data-layout-grid-mode-label attribute.
-       *
-       * @param {int|string} transitionTime
-       *  A string or number determining how long the animation will run.
        */
-      function gridMode(transitionTime) {
-        $layoutBuilder.addClass('layout-builder-grid-mode');
+      function gridMode() {
+        $layoutBuilder.addClass('layout-builder--grid-mode');
         $('[data-layout-grid-mode-label]', context).each((i, element) => {
           const $element = $(element);
 
@@ -241,7 +238,7 @@
               element.childNodes[index].nodeValue = '';
             }
           });
-          $element.children(':not([data-contextual-id])').hide(transitionTime);
+          $element.children(':not([data-contextual-id])').hide(0);
           const adminLabel = document.createElement('h2');
           adminLabel.className = 'layout-builder-block__grid-mode-label';
           adminLabel.innerHTML = $element.attr('data-layout-grid-mode-label');
@@ -255,17 +252,14 @@
        * Live preview mode is the default Layout Builder editor experience.
        * When this mode is switched to from grid mode, the grid mode labels are
        * removed, and hidden block content is made visible.
-       *
-       * @param {int|string} transitionTime
-       *  A string or number determining how long the animation will run.
        */
-      function livePreviewMode(transitionTime) {
-        $layoutBuilder.removeClass('layout-builder-grid-mode');
+      function livePreviewMode() {
+        $layoutBuilder.removeClass('layout-builder--grid-mode');
         $('.layout-builder-block__grid-mode-label').remove();
         $('[data-layout-grid-mode-label]').each((i, element) => {
           $(element)
             .children()
-            .show(transitionTime, () => {
+            .show(0, () => {
               // Bring back any text nodes removed in gridMode().
               if ($(element).data('not-nested-text')) {
                 $(element).prepend($(element).data('not-nested-text'));
@@ -281,10 +275,10 @@
         localStorage.setItem(livePreviewId, isChecked);
 
         if (isChecked) {
-          livePreviewMode('fast');
+          livePreviewMode();
           announce(Drupal.t('Layout Builder editor is in live preview mode.'));
         } else {
-          gridMode('fast');
+          gridMode();
           announce(Drupal.t('Layout Builder editor is in grid mode.'));
         }
       });
@@ -295,7 +289,7 @@
        */
       if (livePreviewActive === 'false') {
         $layoutBuilderLivePreview.attr('checked', false);
-        gridMode(0);
+        gridMode();
       }
     },
   };
diff --git a/core/modules/layout_builder/js/layout-builder.js b/core/modules/layout_builder/js/layout-builder.js
index 9c7fb9a24b..25e3c7f21b 100644
--- a/core/modules/layout_builder/js/layout-builder.js
+++ b/core/modules/layout_builder/js/layout-builder.js
@@ -102,8 +102,8 @@
 
       var livePreviewActive = localStorage.getItem(livePreviewId);
 
-      function gridMode(transitionTime) {
-        $layoutBuilder.addClass('layout-builder-grid-mode');
+      function gridMode() {
+        $layoutBuilder.addClass('layout-builder--grid-mode');
         $('[data-layout-grid-mode-label]', context).each(function (i, element) {
           var $element = $(element);
 
@@ -114,7 +114,7 @@
               element.childNodes[index].nodeValue = '';
             }
           });
-          $element.children(':not([data-contextual-id])').hide(transitionTime);
+          $element.children(':not([data-contextual-id])').hide(0);
           var adminLabel = document.createElement('h2');
           adminLabel.className = 'layout-builder-block__grid-mode-label';
           adminLabel.innerHTML = $element.attr('data-layout-grid-mode-label');
@@ -122,11 +122,11 @@
         });
       }
 
-      function livePreviewMode(transitionTime) {
-        $layoutBuilder.removeClass('layout-builder-grid-mode');
+      function livePreviewMode() {
+        $layoutBuilder.removeClass('layout-builder--grid-mode');
         $('.layout-builder-block__grid-mode-label').remove();
         $('[data-layout-grid-mode-label]').each(function (i, element) {
-          $(element).children().show(transitionTime, function () {
+          $(element).children().show(0, function () {
             if ($(element).data('not-nested-text')) {
               $(element).prepend($(element).data('not-nested-text'));
               $(element).removeData('not-nested-text');
@@ -141,17 +141,17 @@
         localStorage.setItem(livePreviewId, isChecked);
 
         if (isChecked) {
-          livePreviewMode('fast');
+          livePreviewMode();
           announce(Drupal.t('Layout Builder editor is in live preview mode.'));
         } else {
-          gridMode('fast');
+          gridMode();
           announce(Drupal.t('Layout Builder editor is in grid mode.'));
         }
       });
 
       if (livePreviewActive === 'false') {
         $layoutBuilderLivePreview.attr('checked', false);
-        gridMode(0);
+        gridMode();
       }
     }
   };