diff --git a/slynk/slynk.lisp b/slynk/slynk.lisp
index 8f2733b48..3e4115d1c 100644
--- a/slynk/slynk.lisp
+++ b/slynk/slynk.lisp
@@ -3966,7 +3966,8 @@ after each command.")
        (handle-indentation-cache-request c request))
       (multithreaded-connection
        (without-sly-interrupts
-         (send (mconn.indentation-cache-thread c) request))))))
+         (send (mconn.indentation-cache-thread c) request)))
+      (null t))))
 
 (defun indentation-cache-loop (connection)
   (with-connection (connection)