diff --git src/bp-templates/bp-legacy/js/buddypress.js src/bp-templates/bp-legacy/js/buddypress.js
index 38326ccf0..338644fa1 100644
--- src/bp-templates/bp-legacy/js/buddypress.js
+++ src/bp-templates/bp-legacy/js/buddypress.js
@@ -610,7 +610,7 @@ jq(document).ready( function() {
 			ajaxdata = {
 				action: 'new_activity_comment',
 				'cookie': bp_get_cookies(),
-				'_wpnonce_new_activity_comment': jq('#_wpnonce_new_activity_comment' + '_' + comment_id ).val(),
+				'_wpnonce_new_activity_comment': jq('#_wpnonce_new_activity_comment' + '_' + form_id[2] ).val(),
 				'comment_id': comment_id,
 				'form_id': form_id[2],
 				'content': content.val()
diff --git src/bp-templates/bp-nouveau/js/buddypress-activity.js src/bp-templates/bp-nouveau/js/buddypress-activity.js
index 12fb80f83..1e6ded9cc 100644
--- src/bp-templates/bp-nouveau/js/buddypress-activity.js
+++ src/bp-templates/bp-nouveau/js/buddypress-activity.js
@@ -736,7 +736,7 @@ window.bp = window.bp || {};
 
 				comment_data = {
 					action                        : 'new_activity_comment',
-					_wpnonce_new_activity_comment : $( '#_wpnonce_new_activity_comment' + '_' + item_id ).val(),
+					_wpnonce_new_activity_comment : $( '#_wpnonce_new_activity_comment' + '_' + activity_id ).val(),
 					comment_id                    : item_id,
 					form_id                       : activity_id,
 					content                       : comment_content.val()