Index: src/bp-blogs/bp-blogs-activity.php
===================================================================
--- src/bp-blogs/bp-blogs-activity.php
+++ src/bp-blogs/bp-blogs-activity.php
@@ -1281,7 +1281,7 @@
 
 	// Check comment depth and disable if depth is too large.
 	if ( isset( buddypress()->blogs->thread_depth[$comment->item_id] ) ){
-		if ( $comment->mptt_left > buddypress()->blogs->thread_depth[$comment->item_id] ) {
+		if ( bp_activity_get_comment_depth() > buddypress()->blogs->thread_depth[$comment->item_id] ) {
 			$retval = false;
 		}
 	}