--- ngx_http_variables.c.old	2021-07-12 20:11:59.985843678 +0800
+++ ngx_http_variables.c	2021-07-12 20:12:22.881285689 +0800
@@ -282,7 +282,7 @@
 
     { ngx_string("request_completion"), NULL,
       ngx_http_variable_request_completion,
-      0, 0, 0 },
+      0, NGX_HTTP_VAR_NOCACHEABLE, 0 },
 
     { ngx_string("request_body"), NULL,
       ngx_http_variable_request_body,