diff --git a/reg-tests/lua/set_var.vtc b/reg-tests/lua/set_var.vtc
index fc21b41..af4cbf1 100644
--- a/reg-tests/lua/set_var.vtc
+++ b/reg-tests/lua/set_var.vtc
@@ -6,6 +6,12 @@
 
 haproxy h1 -conf {
     global
+        # WT: limit false-positives causing "HTTP header incomplete" due to
+        # idle server connections being randomly used and randomly expiring
+        # under us.
+        tune.idle-pool.shared off
+
+    global
         lua-load ${testdir}/set_var.lua
 
     frontend fe1