diff --git a/packages/core/src/runtime/supervise.ts b/packages/core/src/runtime/supervise.ts
index a97ab37..ed7783a 100644
--- a/packages/core/src/runtime/supervise.ts
+++ b/packages/core/src/runtime/supervise.ts
@@ -54,7 +54,8 @@ export class Supervisor {
             Turn.activeFacet.onStop(() => {
                 const exitReason = this.supervisee?.exitReason;
                 if (!exitReason) {
-                    throw new Error("Expected supervisee to have terminated");
+                    // Supervisor shutdown. Supervisee will exit soon.
+                    return;
                 }
                 if (exitReason.ok && (this.config.restartPolicy === SupervisorRestartPolicy.ON_ERROR_ONLY)) {
                     this.state.value = 'complete';