Index: modules/cache/cache_util.c
===================================================================
--- a/modules/cache/cache_util.c	(revision 1705527)
+++ b/modules/cache/cache_util.c	(revision 1705528)
@@ -1254,7 +1254,6 @@
     headers_out = apr_table_overlay(r->pool, r->headers_out,
                                         r->err_headers_out);
 
-    apr_table_clear(r->err_headers_out);

     headers_out = ap_cache_cacheable_headers(r->pool, headers_out,
                                                   r->server);
Index: modules/cache/mod_cache.c
===================================================================
--- a/modules/cache/mod_cache.c	(revision 1705527)
+++ b/modules/cache/mod_cache.c	(revision 1705528)
@@ -1452,6 +1452,7 @@
          * headers that might have snuck in.
          */
         r->headers_out = ap_cache_cacheable_headers_out(r);
+        apr_table_clear(r->err_headers_out);
 
         /* Merge in our cached headers.  However, keep any updated values. */
         /* take output, overlay on top of cached */