Index: bbp-includes/bbp-reply-functions.php
===================================================================
--- bbp-includes/bbp-reply-functions.php	(revision 3244)
+++ bbp-includes/bbp-reply-functions.php	(working copy)
@@ -269,6 +269,9 @@

 				/** Topic Tags ************************************************/

+				// Just in time manipulation of reply terms before being edited
+				$terms = apply_filters( 'bbp_new_reply_pre_set_terms', $terms, $topic_id );
+
 				// Insert terms
 				$terms = wp_set_post_terms( $topic_id, $terms, $bbp->topic_tag_id, false );

@@ -484,6 +487,9 @@

 			/** Topic Tags ************************************************/

+			// Just in time manipulation of reply terms before being edited
+			$terms = apply_filters( 'bbp_edit_reply_pre_set_terms', $terms, $topic_id );
+
 			// Insert terms
 			$terms = wp_set_post_terms( $topic_id, $terms, $bbp->topic_tag_id, false );