diff --git a/app/Services/AdminNotificationService.php b/app/Services/AdminNotificationService.php
index 505ce1f..8a8885b 100644
--- a/app/Services/AdminNotificationService.php
+++ b/app/Services/AdminNotificationService.php
@@ -23,7 +23,7 @@ class AdminNotificationService
         }
 
         $errorKey = $this->getErrorKey($exception);
-        $throttleMinutes = config('libra.notifications.throttle_minutes', 15);
+        $throttleMinutes = (int) config('libra.notifications.throttle_minutes', 15);
 
         if (Cache::has($errorKey)) {
             return;
diff --git a/docs/tasks/23.md b/docs/tasks/23.md
new file mode 100644
index 0000000..a23e490
--- /dev/null
+++ b/docs/tasks/23.md
@@ -0,0 +1,93 @@
+---
+id: 23
+title: 23 Fix AdminNotificationService Carbon TypeError Masking Exceptions
+status: Done
+date: 2026-09-28
+parent: null
+---
+
+## Description
+
+Investigating a client report of a missing workshop-registration email led to discovering a real
+bug: `App\Services\AdminNotificationService::notifyError()` throws its own `TypeError` whenever
+it runs, which **masks the original exception** it was trying to report and prevents the admin
+notification from ever being sent. Root cause: `config('libra.notifications.throttle_minutes', 15)`
+resolves to `env('ERROR_NOTIFICATION_THROTTLE_MINUTES', 15)` (see `config/libra.php` line 14).
+Production's `.env` has `ERROR_NOTIFICATION_THROTTLE_MINUTES=15` set — Laravel's `env()` helper
+does not cast a numeric-looking string to an int, so this returns the **string** `"15"`, not the
+int `15`. That string is then passed to `now()->addMinutes($throttleMinutes)` in
+`AdminNotificationService::notifyError()` (line 32), and Carbon 3.11 (this project's installed
+version, per `composer.lock`) requires `addMinutes()`'s argument to be `int|float` — passing a
+string throws `TypeError: Carbon\Carbon::rawAddUnit(): Argument #3 ($value) must be of type
+int|float, string given`.
+
+This is a live production bug, confirmed via `storage/logs/laravel.log` on h1
+(`/home/libra/public_html/storage/logs/laravel.log`, entries timestamped `2026-09-27 21:35:26`
+and `21:40:31`) — every exception that reaches `Handler->report()` and is judged
+notify-worthy by `AdminNotificationService::shouldNotifyAdmin()` (e.g. any
+`Symfony\Component\Mailer\Exception\TransportExceptionInterface`, or a critical
+`QueryException`) currently crashes this method instead of sending the notification, and the
+crash happens **before** `Cache::put()` on line 32 ever executes, so the throttle-dedup cache key
+is never written — meaning this crash also can't self-heal or throttle, it fires on every single
+qualifying exception, indefinitely, until fixed.
+
+**File to modify:** `app/Services/AdminNotificationService.php`
+
+Current (lines 25-32):
+```php
+        $errorKey = $this->getErrorKey($exception);
+        $throttleMinutes = config('libra.notifications.throttle_minutes', 15);
+
+        if (Cache::has($errorKey)) {
+            return;
+        }
+
+        Cache::put($errorKey, true, now()->addMinutes($throttleMinutes));
+```
+
+Change to cast the config value to an int before use:
+```php
+        $errorKey = $this->getErrorKey($exception);
+        $throttleMinutes = (int) config('libra.notifications.throttle_minutes', 15);
+
+        if (Cache::has($errorKey)) {
+            return;
+        }
+
+        Cache::put($errorKey, true, now()->addMinutes($throttleMinutes));
+```
+
+This is the only line that changes. No other method, no other file.
+
+## Acceptance Criteria
+
+- [x] `app/Services/AdminNotificationService.php`'s `$throttleMinutes` assignment casts the config
+      value with `(int)`
+- [x] A test constructs `AdminNotificationService` and calls `notifyError()` with a throwable that
+      makes `shouldNotifyAdmin()` return true (e.g. a mock/stub implementing
+      `Symfony\Component\Mailer\Exception\TransportExceptionInterface`, or simply an instance of a
+      class implementing `App\Contracts\ShouldNotifyAdmin`), with
+      `config(['libra.notifications.throttle_minutes' => '15'])` explicitly set as a **string** in
+      the test (reproducing production's actual condition — `env()` never returns a string this
+      way in tests, so it must be set explicitly to catch this class of bug) — the call completes
+      without throwing, and a mail notification is sent (assert via `Notification::fake()` /
+      `Mail::fake()` as appropriate for however `SystemErrorNotification` delivers)
+- [x] The same test, run against the **old** code (temporarily, to confirm the test actually
+      catches the bug) throws a `TypeError` — state in the completion report that this was
+      confirmed, per this task's RED step
+
+## QA Verification (2026-09-28)
+
+All 3 acceptance criteria verified directly:
+1. Confirmed `(int)` cast present at `app/Services/AdminNotificationService.php:26`.
+2. Ran `tests/Unit/Services/AdminNotificationServiceTest.php`'s new test
+   (`does not throw and still sends notification when throttle_minutes config is a string`) —
+   passed.
+3. Temporarily removed the `(int)` cast, re-ran the same test — reproduced the exact TypeError
+   (`Carbon\Carbon::rawAddUnit(): Argument #3 ($value) must be of type int|float, string given`),
+   confirming RED. Restored the `(int)` cast. Full suite re-run: 17/17 passed. `git diff` confirms
+   only the single intended line differs from the pre-fix version.
+
+## Sub-tasks
+
+None.
diff --git a/docs/tasks/statuses.md b/docs/tasks/statuses.md
index a7d2f2a..3e24cf0 100644
--- a/docs/tasks/statuses.md
+++ b/docs/tasks/statuses.md
@@ -134,3 +134,4 @@
 | 20 | 20 Nablus Workshop Form - Match Site Background and Card Styling | Done |
 | 21 | 21 Nablus Workshop Form - Flyer Size Adjustment | Done |
 | 22 | 22 Fix Footer Address - Add Missing Street Name | Done |
+| 23 | 23 Fix AdminNotificationService Carbon TypeError Masking Exceptions | Done |
diff --git a/tests/Unit/Services/AdminNotificationServiceTest.php b/tests/Unit/Services/AdminNotificationServiceTest.php
index 209f4ee..44c2a0e 100644
--- a/tests/Unit/Services/AdminNotificationServiceTest.php
+++ b/tests/Unit/Services/AdminNotificationServiceTest.php
@@ -184,4 +184,27 @@ describe('notifyError', function () {
 
         Notification::assertSentOnDemandTimes(SystemErrorNotification::class, 2);
     });
+
+    it('does not throw and still sends notification when throttle_minutes config is a string', function () {
+        // Reproduces a live production bug: env('ERROR_NOTIFICATION_THROTTLE_MINUTES', 15) returns
+        // the string "15" (env() never casts numeric-looking strings to int), which used to be
+        // passed straight into now()->addMinutes(), and Carbon 3.11 throws a TypeError for a
+        // string argument there. That TypeError masked the original exception being reported and
+        // notifyError() never actually sent the admin notification.
+        Notification::fake();
+        Cache::flush();
+        config(['libra.notifications.throttle_minutes' => '15']);
+
+        $service = new AdminNotificationService;
+        $exception = new TransportException('SMTP error');
+
+        $service->notifyError($exception);
+
+        Notification::assertSentOnDemand(
+            SystemErrorNotification::class,
+            function ($notification, $channels, $notifiable) {
+                return $notifiable->routes['mail'] === 'admin@test.com';
+            }
+        );
+    });
 });