diff --git a/controller/src/history.rs b/controller/src/history.rs
index 89f96ea1..4405869a 100644
--- a/controller/src/history.rs
+++ b/controller/src/history.rs
@@ -274,9 +274,11 @@ impl History {
                 Some(RefStatus::Errored(exception)) => {
                     // We know that this invocation hasn't been completed yet, so we can
                     // directly call set_exception on it.
-                    invocation.set_exception(exception.clone());
-                    results.push((seq, Some(Err(exception.clone()))));
-                    invocation.reported = true;
+                    if !invocation.reported {
+                        invocation.set_exception(exception.clone());
+                        results.push((seq, Some(Err(exception.clone()))));
+                        invocation.reported = true;
+                    }
                 }
                 Some(RefStatus::Invoked(invoked_seq)) => {
                     if let Some(invocation) = self.invocations.get_mut(invoked_seq) {