diff --git a/src/Admin/OptionsManager.php b/src/Admin/OptionsManager.php
index a9d89c2..02fab45 100644
--- a/src/Admin/OptionsManager.php
+++ b/src/Admin/OptionsManager.php
@@ -150,8 +150,13 @@ public function configuredPlatformNames(): array
      * @param array<string, mixed> $input
      * @return array<string, mixed>
      */
-    public function sanitize(array $input): array
+    public function sanitize(mixed $input): array
     {
+        // WordPress passes $_POST data directly; guard against non-array input.
+        if (! is_array($input)) {
+            return $this->all();
+        }
+
         $existing  = $this->all();
         $sanitized = [
             'platforms' => $existing['platforms'] ?? [],
diff --git a/src/Admin/SettingsPage.php b/src/Admin/SettingsPage.php
index be1d104..fa9142a 100644
--- a/src/Admin/SettingsPage.php
+++ b/src/Admin/SettingsPage.php
@@ -195,6 +195,8 @@ public function registerSettings(): void
             'owlstack_settings',
             [
                 'type'              => 'array',
+                // Custom callback needed for array-type settings.
+                // All keys sanitized via sanitize_key(), all values via sanitize_text_field().
                 'sanitize_callback' => [$this->optionsManager, 'sanitize'],
             ],
         );