Index: openacs-4/packages/acs-developer-support/tcl/acs-developer-support-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/acs-developer-support/tcl/acs-developer-support-procs.tcl,v
diff -u -N -r1.64.2.12 -r1.64.2.13
--- openacs-4/packages/acs-developer-support/tcl/acs-developer-support-procs.tcl	28 Dec 2021 17:02:25 -0000	1.64.2.12
+++ openacs-4/packages/acs-developer-support/tcl/acs-developer-support-procs.tcl	19 Jan 2022 11:13:12 -0000	1.64.2.13
@@ -457,8 +457,10 @@
     if { [ds_enabled_p] && [ds_collection_enabled_p] } {
         ds_add conn end [ns_time] endclicks [clock clicks -microseconds]
 
-        ds_add oheaders \
-            {*}[ns_set array [ad_conn outputheaders]]
+        set args [ns_set array [ad_conn outputheaders]]
+        if {[llength $args] > 0} {
+            ds_add oheaders {*}$args
+        }
 
         foreach param { browser_id validated session_id user_id } {
             global ad_sec_$param