diff --git a/app/Config/Routes.php b/app/Config/Routes.php
index 8f86bb7..b02827a 100644
--- a/app/Config/Routes.php
+++ b/app/Config/Routes.php
@@ -538,6 +538,9 @@ $routes->get('grading/(:segment)/(:num)/(:num)', 'View\GradingController::show/$
 $routes->post('grading/update', 'View\GradingController::update');
 $routes->get('grading', 'View\GradingController::grading');
 $routes->post('grading/toggle-score-lock', 'View\GradingController::toggleScoreLock', ['filter' => 'auth:read']);
+$routes->get('grading/toggle-score-lock', static function () {
+    return 'GET route hit. Something is calling this route incorrectly.';
+});
 $routes->post('grading/lock-all-scores', 'View\GradingController::lockAllScores', ['filter' => 'auth:read']);
 $routes->post('grading/release-scores', 'View\GradingController::toggleParentScoresRelease', ['filter' => 'auth:read']);
 $routes->post('grading/refresh-semester-scores', 'View\GradingController::refreshSemesterScores', ['filter' => 'auth:read']);
diff --git a/app/Controllers/ProofreadController.php b/app/Controllers/ProofreadController.php
index d8e64a4..1716ae6 100644
--- a/app/Controllers/ProofreadController.php
+++ b/app/Controllers/ProofreadController.php
@@ -10,8 +10,13 @@ class ProofreadController extends ResourceController
     {
         // Basic per-IP throttling: 10 requests per minute
         $throttler = service('throttler');
-        $key = 'proofread-' . $this->request->getIPAddress();
-        if (!$throttler->check($key, 10, MINUTE)) {
+
+        // Cache/throttler keys cannot contain reserved characters.
+        // Raw IPv6 addresses contain ":", so hash the IP first.
+        $ip = $this->request->getIPAddress();
+        $key = 'proofread-' . hash('sha256', $ip);
+
+        if (! $throttler->check($key, 10, MINUTE)) {
             return $this->respond([
                 'ok' => false,
                 'error' => 'Too many requests. Try again in a minute.',
@@ -20,8 +25,9 @@ class ProofreadController extends ResourceController
         }
 
         // Accept form-urlencoded payload to play nicely with CSRF protection
-        $validation = service('validation');
         $payload = sanitize_request_value($this->request->getPost(['text']));
+
+        $validation = service('validation');
         $validation->setRules([
             'text' => 'required|min_length[1]|max_length[20000]',
         ]);
@@ -36,20 +42,34 @@ class ProofreadController extends ResourceController
 
         $text = (string) $payload['text'];
 
-        $client = \Config\Services::curlrequest(['timeout' => 10]);
+        $client = \Config\Services::curlrequest([
+            'timeout' => 10,
+        ]);
 
         try {
             $resp = $client->post('https://api.languagetool.org/v2/check', [
-                'headers' => ['Content-Type' => 'application/x-www-form-urlencoded'],
+                'headers' => [
+                    'Content-Type' => 'application/x-www-form-urlencoded',
+                ],
                 'form_params' => [
                     'text'     => $text,
                     'language' => 'en-US',
                 ],
             ]);
 
+            $result = json_decode($resp->getBody(), true);
+
+            if (json_last_error() !== JSON_ERROR_NONE) {
+                return $this->respond([
+                    'ok' => false,
+                    'error' => 'Invalid response from proofread service.',
+                    'csrfHash' => csrf_hash(),
+                ], 502);
+            }
+
             return $this->respond([
                 'ok' => true,
-                'result' => json_decode($resp->getBody(), true),
+                'result' => $result,
                 'csrfHash' => csrf_hash(),
             ]);
         } catch (\Throwable $e) {
@@ -60,4 +80,4 @@ class ProofreadController extends ResourceController
             ], 502);
         }
     }
-}
+}
\ No newline at end of file
diff --git a/app/Controllers/View/ScoreCommentController.php b/app/Controllers/View/ScoreCommentController.php
index 5f9d0ae..a1390b4 100644
--- a/app/Controllers/View/ScoreCommentController.php
+++ b/app/Controllers/View/ScoreCommentController.php
@@ -231,18 +231,36 @@ class ScoreCommentController extends BaseController
             $rawCommentsBuilder->groupEnd();
         }
 
+        if (!$isAllSections && $classSectionId > 0) {
+            // Prefer the exact class-section row over legacy NULL class-section rows.
+            // Without this, duplicate rows can overwrite each other unpredictably.
+            $rawCommentsBuilder
+                ->orderBy("CASE WHEN class_section_id = {$classSectionId} THEN 0 ELSE 1 END", '', false)
+                ->orderBy('id', 'DESC');
+        } else {
+            $rawCommentsBuilder->orderBy('id', 'DESC');
+        }
+
         $rawComments = $rawCommentsBuilder->findAll();
 
         $existingAttendance = [];
         foreach ($rawComments as $c) {
-            $sid = (int)$c['student_id'];
-            $typ = (string)$c['score_type'];
+            $sid = (int) $c['student_id'];
+            $typ = strtolower(trim((string) $c['score_type']));
+
+            // The query is ordered with the best row first. Do not let legacy/older
+            // duplicate rows overwrite the selected comment/review.
+            if (isset($comments[$sid][$typ])) {
+                continue;
+            }
+
             $comments[$sid][$typ] = [
                 'comment'        => $c['comment'] ?? null,
                 'comment_review' => $c['comment_review'] ?? null,
                 'commented_by'   => $c['commented_by'] ?? null,
                 'reviewed_by'    => $c['reviewed_by'] ?? null,
             ];
+
             if ($typ === 'attendance') {
                 $existingAttendance[$sid] = $c;
             }
@@ -435,6 +453,16 @@ class ScoreCommentController extends BaseController
                 $existingQuery->groupEnd();
             }
 
+            if (is_int($classSectionId) && $classSectionId > 0) {
+                // Prefer updating the real class-section row. If only a legacy NULL row
+                // exists, it will be picked next and migrated to the class section below.
+                $existingQuery
+                    ->orderBy("CASE WHEN class_section_id = {$classSectionId} THEN 0 ELSE 1 END", '', false)
+                    ->orderBy('id', 'DESC');
+            } else {
+                $existingQuery->orderBy('id', 'DESC');
+            }
+
             $existing = $existingQuery->first();
 
             $data = [
diff --git a/app/Views/grading/comments.php b/app/Views/grading/comments.php
index dd5dd19..f20514d 100644
--- a/app/Views/grading/comments.php
+++ b/app/Views/grading/comments.php
@@ -32,7 +32,7 @@ $lockAttr = $scoresLocked ? 'disabled' : '';
             </div>
         <?php endif; ?>
  <div class="d-flex justify-content-between mt-4 flex-wrap gap-2">
-                <button type="submit" class="btn btn-success" <?= $lockAttr ?>>
+                <button type="submit" form="commentsForm" class="btn btn-success" <?= $lockAttr ?>>
                     <i class="bi bi-save"></i> Save All Changes
                 </button>
                 <a href="<?= base_url('/grading') ?>" class="btn btn-secondary">