diff --git a/server/harness.c b/server/harness.c
index 5e41527..ea222b7 100644
--- a/server/harness.c
+++ b/server/harness.c
@@ -125,9 +125,10 @@ typedef struct nap_context_t_ {
 void nap_isr(int fd, short what, void *arg) {
   nap_context_t *context = arg;
   //info("nap_isr %p\n", p);
-  assert((context->p->state == PROCESS_WAITING) && (context->p->wait_flags & EV_TIMEOUT));
-  context->timeout_fired = 1;
-  enqueue_runlist(context->p);
+  if ((context->p->state == PROCESS_WAITING) && (context->p->wait_flags & EV_TIMEOUT)) {
+    context->timeout_fired = 1;
+    enqueue_runlist(context->p);
+  }
 }
 
 int nap(long millis) {