diff --git a/public/s/js/sidebar-activity.js b/public/s/js/sidebar-activity.js
index 3b65396..43c0993 100644
--- a/public/s/js/sidebar-activity.js
+++ b/public/s/js/sidebar-activity.js
@@ -499,6 +499,19 @@
                 </div>`;
         }
 
+        // Robust fallback for is_long if server didn't provide it, plus inline media checks
+        let isLong = c.is_long;
+        const rawText = c.content || c.body || '';
+        if (isLong === undefined) {
+            isLong = rawText.length > 120 
+                || rawText.split('\n').length > 2 
+                || (c.files && c.files.length > 0);
+        }
+        // Always force isLong if there are inline media tags that expand vertically
+        if (!isLong && /\[(video|audio|youtube|img)\]|!\[|https?:\/\//i.test(rawText)) {
+            isLong = true;
+        }
+
         return `
             <div class="comment" id="sc${c.id}">
                 <div class="comment-body">
@@ -511,7 +524,7 @@
                         </div>
                         <span class="comment-time timeago" tooltip="${fullDate}" style="font-size: 0.75em;"${tsAttr}>${timeStr}</span>
                     </div>
-                    <div class="comment-content${c.is_long ? ' has-overflow' : ''}"><div class="comment-content-inner">${displayContent}${attachmentsHtml}${pollHtml}</div><button class="read-more-btn"${c.is_long ? ' style="display:block"' : ''}>${window.f0ckI18n?.sidebar_read_more || 'read more'}</button></div>
+                    <div class="comment-content${isLong ? ' has-overflow' : ''}"><div class="comment-content-inner">${displayContent}${attachmentsHtml}${pollHtml}</div><button class="read-more-btn"${isLong ? ' style="display:block"' : ''}>${window.f0ckI18n?.sidebar_read_more || 'read more'}</button></div>
                     ${itemPreview}
                 </div>
             </div>`;
diff --git a/src/inc/routes/comments.mjs b/src/inc/routes/comments.mjs
index 1cd0ad0..6415b13 100644
--- a/src/inc/routes/comments.mjs
+++ b/src/inc/routes/comments.mjs
@@ -614,7 +614,8 @@ export default (router, tpl) => {
             // sidebar renders the correct clamped state immediately on first paint.
             const activityIsLong = content.length > 120
                 || content.split('\n').length > 2
-                || activityFiles.length > 0;
+                || activityFiles.length > 0
+                || /\[(video|audio|youtube|img)\]|!\[|https?:\/\//i.test(content);
             db.notify('activity', JSON.stringify({
                 user_id: req.session.id,
                 item_id: item_id,
@@ -1103,7 +1104,8 @@ export default (router, tpl) => {
                 // attachments (images/video) will also push height above the limit.
                 const isLong = commentContent.length > 120
                     || commentContent.split('\n').length > 2
-                    || commentFiles.length > 0;
+                    || commentFiles.length > 0
+                    || /\[(video|audio|youtube|img)\]|!\[|https?:\/\//i.test(commentContent);
 
                 return {
                     ...c,