diff --git a/syndicate/dataflow.rkt b/syndicate/dataflow.rkt
index 67bc9e0..ac94b68 100644
--- a/syndicate/dataflow.rkt
+++ b/syndicate/dataflow.rkt
@@ -54,11 +54,14 @@
     (define workset (dataflow-graph-damaged-nodes g))
     (when (not (hash-empty? workset))
       (set-dataflow-graph-damaged-nodes! g (hash))
+      (define updated (make-hash))
       (hash-for-each workset
                      (lambda (object-id _)
                        (for [(subject-id
                               (in-hashset-values (dataflow-graph-edges-forward g) object-id))]
-                         (dataflow-forget-subject! g subject-id)
-                         (parameterize ((current-dataflow-subject-id subject-id))
-                           (repair-node! subject-id)))))
+                         (when (not (hash-has-key? updated subject-id))
+                           (hash-set! updated subject-id #t)
+                           (dataflow-forget-subject! g subject-id)
+                           (parameterize ((current-dataflow-subject-id subject-id))
+                             (repair-node! subject-id))))))
       (loop))))