diff --git a/.gitignore b/.gitignore
index 7ff179d3..a890db7e 100755
--- a/.gitignore
+++ b/.gitignore
@@ -10,3 +10,6 @@ artifacts
 classes/Visualizer/Gutenberg/build
 classes/Visualizer/ChartBuilder/build
 classes/Visualizer/D3Renderer/build
+
+# Local wp-env port pinning (per-checkout).
+.wp-env.override.json
diff --git a/.wp-env.json b/.wp-env.json
index 23d552f6..dc0e3fc8 100644
--- a/.wp-env.json
+++ b/.wp-env.json
@@ -6,8 +6,7 @@
   ],
   "themes": [],
   "mappings": {
-    "wp-content/mu-plugins/visualizer-e2e-enable-database-source.php": "./tests/e2e/config/enable-database-source.php",
-    "wp-content/mu-plugins/visualizer-e2e-force-lazy-render.php": "./tests/e2e/config/force-lazy-render.php"
+    "wp-content/mu-plugins": "./tests/e2e/config/mu-plugins"
   },
   "config": {
     "WP_DEBUG": true,
diff --git a/tests/e2e/config/enable-database-source.php b/tests/e2e/config/mu-plugins/enable-database-source.php
similarity index 100%
rename from tests/e2e/config/enable-database-source.php
rename to tests/e2e/config/mu-plugins/enable-database-source.php
diff --git a/tests/e2e/config/force-lazy-render.php b/tests/e2e/config/mu-plugins/force-lazy-render.php
similarity index 100%
rename from tests/e2e/config/force-lazy-render.php
rename to tests/e2e/config/mu-plugins/force-lazy-render.php
diff --git a/tests/e2e/playwright.config.js b/tests/e2e/playwright.config.js
index a39cddd1..d0838fd1 100644
--- a/tests/e2e/playwright.config.js
+++ b/tests/e2e/playwright.config.js
@@ -7,6 +7,15 @@ import os from 'os';
 import { fileURLToPath } from 'url';
 import { defineConfig, devices } from '@playwright/test';
 
+// The tests instance may be pinned to a non-default port in .wp-env.override.json
+// (8889 is often taken by another checkout). Target whatever wp-env actually bound.
+let testsPort = process.env.WP_ENV_TESTS_PORT;
+try {
+	testsPort ??= require( '../../.wp-env.override.json' ).testsPort;
+} catch ( e ) {} // No override file, fall back to the wp-env default.
+testsPort = Number( testsPort ) || 8889;
+process.env.WP_BASE_URL ??= `http://localhost:${ testsPort }`;
+
 /**
  * WordPress dependencies
  */
@@ -14,6 +23,7 @@ const baseConfig = require( '@wordpress/scripts/config/playwright.config' );
 
 const config = defineConfig( {
 	...baseConfig,
+	webServer: { ...baseConfig.webServer, port: testsPort },
 	reporter: process.env.CI
 		? [ [ 'github' ], [ './config/flaky-tests-reporter.js' ] ]
 		: 'list',
diff --git a/tests/e2e/specs/lazy-render.spec.js b/tests/e2e/specs/lazy-render.spec.js
index 55b6b8db..df743b45 100644
--- a/tests/e2e/specs/lazy-render.spec.js
+++ b/tests/e2e/specs/lazy-render.spec.js
@@ -38,8 +38,11 @@ test.describe( 'Lazy rendered charts (frontend)', () => {
 	}
 
 	async function triggerLazyLoader( page ) {
-		// Scripts are swapped to `data-visualizer-script` placeholders.
-		await expect( page.locator( 'script[data-visualizer-script]' ).first() ).toBeAttached();
+		// Assert lazy rendering is on via the container class, not the
+		// `data-visualizer-script` placeholders: those are swapped away by the
+		// first user interaction, and Chromium fires a real `mouseover` right
+		// after navigation whenever the cursor sits over the page.
+		await expect( page.locator( '.visualizer-lazy-render' ).first() ).toBeAttached();
 
 		// The loader starts on the first user interaction.
 		await page.evaluate( () => window.dispatchEvent( new Event( 'scroll' ) ) );