diff --git a/frontend/tests/e2e/email-templates.spec.ts b/frontend/tests/e2e/email-templates.spec.ts
index 48fac51..c62b10f 100644
--- a/frontend/tests/e2e/email-templates.spec.ts
+++ b/frontend/tests/e2e/email-templates.spec.ts
@@ -25,14 +25,18 @@ test.describe('Editing the customer emails', () => {
       'Favorited item sold',
       'Favorited item withdrawn',
       'Cart reminder',
-      'Email address changed'
+      'Email address changed',
+      // Added in #337, and the reason these are matched on the whole
+      // accessible name rather than as substrings: it extends the label above
+      // it, so an unanchored match resolved to both tabs.
+      'Email address changed by the shop'
     ]) {
-      await expect(adminEmails.railTab(new RegExp(label))).toBeVisible();
+      await expect(adminEmails.railTab(label)).toBeVisible();
     }
 
     // Only a customised template is marked, so which ones have been changed is
     // visible without opening each one. An untouched template carries nothing.
-    await expect(adminEmails.railTab(/Password reset/)).toBeVisible();
+    await expect(adminEmails.railTab('Password reset')).toBeVisible();
     await expect(adminEmails.customisedTab('Password reset')).toHaveCount(0);
   });
 
diff --git a/frontend/tests/e2e/pages/AdminEmails.ts b/frontend/tests/e2e/pages/AdminEmails.ts
index 6bb62c7..c4044a6 100644
--- a/frontend/tests/e2e/pages/AdminEmails.ts
+++ b/frontend/tests/e2e/pages/AdminEmails.ts
@@ -1,5 +1,29 @@
 import { FrameLocator, Locator, Page, expect } from '@playwright/test';
 
+/**
+ * A matcher for one template label, against a tab's *whole* accessible name.
+ *
+ * A tab is named for its template, plus the word "Customised" once it has been
+ * edited — the dot beside it carries that as an aria-label, so the state is not
+ * colour-only.
+ *
+ * Anchored at both ends, which is the entire point of this function. The
+ * locators here used to build an unanchored regex from the label, so a template
+ * whose name merely *began* with another's matched both. Adding "Email address
+ * changed by the shop" alongside "Email address changed" broke a passing test
+ * with a strict-mode violation naming the assertion rather than the new
+ * template — the same shape as the switch locator that silently retargeted in
+ * #317, and the same cost to diagnose.
+ *
+ * The escape matters for the same reason: these labels are copy, and copy
+ * acquires brackets and full stops eventually.
+ */
+function nameMatching(label: string, options: { customised?: boolean } = {}): RegExp {
+  const escaped = label.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
+  const suffix = options.customised ? '\\s+Customised' : '(?:\\s+Customised)?';
+  return new RegExp(`^${escaped}${suffix}$`);
+}
+
 /**
  * The Emails tab: a vertical rail of template types and one editor at a time.
  *
@@ -30,13 +54,30 @@ export class AdminEmails {
     return this.page.getByRole('button', { name: `Insert {{${name}}}` });
   }
 
-  /** One template's entry in the rail. */
-  railTab(label: string | RegExp): Locator {
-    return this.page.getByRole('tab', { name: label });
+  /**
+   * One template's entry in the rail, matched on its whole accessible name.
+   *
+   * A tab's accessible name is the template's label, plus the word "Customised"
+   * when it has been edited — the dot beside it carries that as an aria-label so
+   * the state is not colour-only.
+   *
+   * Anchored at both ends, which is the point of this helper rather than a bare
+   * substring match. These locators used to build an unanchored regex from the
+   * label, so a template whose name merely *began* with another's matched both.
+   * Adding "Email address changed by the shop" beside "Email address changed"
+   * broke a passing test with a strict-mode violation, and the failure named the
+   * assertion rather than the new template — the same shape as the switch
+   * locator that silently retargeted in #317.
+   *
+   * The escape matters for the same reason: a label is copy, and copy acquires
+   * brackets and full stops eventually.
+   */
+  railTab(label: string): Locator {
+    return this.page.getByRole('tab', { name: nameMatching(label) });
   }
 
   customisedTab(label: string): Locator {
-    return this.page.getByRole('tab', { name: new RegExp(`${label}.*Customised`) });
+    return this.page.getByRole('tab', { name: nameMatching(label, { customised: true }) });
   }
 
   subject(label: string): Locator {
@@ -65,7 +106,7 @@ export class AdminEmails {
    * resolved mid-swap finds the outgoing one.
    */
   async openTemplate(label: string): Promise<void> {
-    await this.railTab(new RegExp(label)).click();
+    await this.railTab(label).click();
     await expect(this.subject(label)).toBeVisible();
   }
 }