diff --git a/framework/core/src/Post/Access/PostPolicy.php b/framework/core/src/Post/Access/PostPolicy.php
index ff2768625..9c5b5e812 100644
--- a/framework/core/src/Post/Access/PostPolicy.php
+++ b/framework/core/src/Post/Access/PostPolicy.php
@@ -58,7 +58,7 @@ class PostPolicy extends AbstractPolicy
 
             if ($allowEditing === '-1'
                 || ($allowEditing === 'reply' && $post->number >= $post->discussion->last_post_number)
-                || ($post->created_at->diffInMinutes(new Carbon) < $allowEditing)) {
+                || (is_numeric($allowEditing) && $post->created_at->diffInMinutes(new Carbon) < $allowEditing)) {
                 return $this->allow();
             }
         }
diff --git a/framework/core/tests/integration/post/PostPolicyTest.php b/framework/core/tests/integration/post/PostPolicyTest.php
new file mode 100644
index 000000000..c750ebcba
--- /dev/null
+++ b/framework/core/tests/integration/post/PostPolicyTest.php
@@ -0,0 +1,124 @@
+<?php
+
+/*
+ * This file is part of Flarum.
+ *
+ * For detailed copyright and license information, please view the
+ * LICENSE file that was distributed with this source code.
+ */
+
+namespace Flarum\Tests\integration\post;
+
+use Carbon\Carbon;
+use Flarum\Post\Post;
+use Flarum\Testing\integration\RetrievesAuthorizedUsers;
+use Flarum\Testing\integration\TestCase;
+use Flarum\User\User;
+
+class PostPolicyTest extends TestCase
+{
+    use RetrievesAuthorizedUsers;
+
+    /**
+     * @inheritDoc
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->prepareDatabase([
+            'discussions' => [
+                ['id' => 1, 'title' => 'Editable discussion', 'created_at' => Carbon::parse('2021-11-01 13:00:00')->toDateTimeString(), 'user_id' => 2, 'first_post_id' => 1, 'comment_count' => 2, 'is_private' => 0, 'last_post_number' => 2],
+            ],
+            'posts' => [
+                ['id' => 1, 'discussion_id' => 1, 'number' => 1, 'created_at' => Carbon::parse('2021-11-01 13:00:00')->toDateTimeString(), 'user_id' => 2, 'type' => 'comment', 'content' => '<t></t>'],
+                ['id' => 2, 'discussion_id' => 1, 'number' => 2, 'created_at' => Carbon::parse('2021-11-01 13:00:03')->toDateTimeString(), 'user_id' => 2, 'type' => 'comment', 'content' => '<t></t>'],
+            ],
+            'users' => [
+                $this->normalUser(),
+            ]
+        ]);
+    }
+
+    protected function tearDown(): void
+    {
+        parent::tearDown();
+
+        Carbon::setTestNow();
+    }
+
+    /**
+     * @test
+     */
+    public function edit_indefinitely()
+    {
+        $this->setting('allow_post_editing', '-1');
+        $this->app();
+
+        $user = User::findOrFail(2);
+        $earlierPost = Post::findOrFail(1);
+        $lastPost = Post::findOrFail(2);
+
+        // Date close to "now"
+        Carbon::setTestNow('2021-11-01 13:00:05');
+
+        $this->assertTrue($user->can('edit', $earlierPost));
+        $this->assertTrue($user->can('edit', $lastPost));
+
+        // Date further into the future
+        Carbon::setTestNow('2025-01-01 13:00:00');
+
+        $this->assertTrue($user->can('edit', $earlierPost));
+        $this->assertTrue($user->can('edit', $lastPost));
+    }
+
+    /**
+     * @test
+     */
+    public function edit_until_reply()
+    {
+        $this->setting('allow_post_editing', 'reply');
+        $this->app();
+
+        $user = User::findOrFail(2);
+        $earlierPost = Post::findOrFail(1);
+        $lastPost = Post::findOrFail(2);
+
+        // Date close to "now"
+        Carbon::setTestNow('2021-11-01 13:00:05');
+
+        $this->assertFalse($user->can('edit', $earlierPost));
+        $this->assertTrue($user->can('edit', $lastPost));
+
+        // Date further into the future
+        Carbon::setTestNow('2025-01-01 13:00:00');
+
+        $this->assertFalse($user->can('edit', $earlierPost));
+        $this->assertTrue($user->can('edit', $lastPost));
+    }
+
+    /**
+     * @test
+     */
+    public function edit_10_minutes()
+    {
+        $this->setting('allow_post_editing', '10');
+        $this->app();
+
+        $user = User::findOrFail(2);
+        $earlierPost = Post::findOrFail(1);
+        $lastPost = Post::findOrFail(2);
+
+        // Date close to "now"
+        Carbon::setTestNow('2021-11-01 13:00:05');
+
+        $this->assertTrue($user->can('edit', $earlierPost));
+        $this->assertTrue($user->can('edit', $lastPost));
+
+        // Date further into the future
+        Carbon::setTestNow('2025-01-01 13:00:00');
+
+        $this->assertFalse($user->can('edit', $earlierPost));
+        $this->assertFalse($user->can('edit', $lastPost));
+    }
+}