commit 95ea6dd7a4aeb13263edd410f16c3aa1c646c645
Author: Lubos Uhliarik <luhliari@redhat.com>
Date:   Wed Nov 13 12:47:00 2019 +0100

    Also avoid adding the Set-Cookie header in both r->headers_out and
    r->err_headers_out in ap_cookie_remove and ap_cookie_remove2 functions
    to avoid duplication in HTTP response.

diff --git a/modules/session/mod_session_cookie.c b/modules/session/mod_session_cookie.c
index 36168b7ead..25ca16e242 100644
--- a/modules/session/mod_session_cookie.c
+++ b/modules/session/mod_session_cookie.c
@@ -68,7 +68,7 @@ static apr_status_t session_cookie_save(request_rec * r, session_rec * z)
                             NULL);
         }
         else {
-            ap_cookie_remove(r, conf->name, conf->name_attrs, r->headers_out,
+            ap_cookie_remove(r, conf->name, conf->name_attrs,
                              r->err_headers_out, NULL);
         }
     }
@@ -82,7 +82,7 @@ static apr_status_t session_cookie_save(request_rec * r, session_rec * z)
         }
         else {
             ap_cookie_remove2(r, conf->name2, conf->name2_attrs,
-                              r->headers_out, r->err_headers_out, NULL);
+                              r->err_headers_out, NULL);
         }
     }