diff --git a/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf b/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf
index 7d11f3df9..d6e0624ef 100644
--- a/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf
+++ b/net/haproxy/src/opnsense/service/templates/OPNsense/HAProxy/haproxy.conf
@@ -131,7 +131,7 @@
 {%                 if acl_data.caseSensitive|default('0') == '0' %}
 {%                   do acl_options.append('-i') %}
 {%                 endif %}
-{%                 do acl_options.append('acl_data.hdr_sub) %}
+{%                 do acl_options.append(acl_data.hdr_sub) %}
 {%               else %}
 {%                 set acl_enabled = '0' %}
     # ERROR: missing parameters