diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 0fef2261c537d..eb48876e4d1e1 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -672,8 +672,8 @@ public function htmlattributes() {
             $hook->add_attribute('xmlns', 'http://www.w3.org/1999/xhtml');
         }
 
-        di::get(hook_manager::class)->dispatch($hook);
         $hook->process_legacy_callbacks();
+        di::get(hook_manager::class)->dispatch($hook);
 
         foreach ($hook->get_attributes() as $key => $val) {
             $val = s($val);
@@ -706,8 +706,8 @@ public function standard_head_html() {
         // must always return a string containing valid html head content.
 
         $hook = new \core\hook\output\before_standard_head_html_generation($this);
-        di::get(hook_manager::class)->dispatch($hook);
         $hook->process_legacy_callbacks();
+        di::get(hook_manager::class)->dispatch($hook);
 
         // Allow a url_rewrite plugin to setup any dynamic head content.
         if (isset($CFG->urlrewriteclass) && !isset($CFG->upgraderunning)) {
@@ -820,8 +820,8 @@ public function standard_top_of_body_html() {
 
         // Allow components to add content to the top of the body.
         $hook = new before_standard_top_of_body_html_generation($this, $output);
-        di::get(hook_manager::class)->dispatch($hook);
         $hook->process_legacy_callbacks();
+        di::get(hook_manager::class)->dispatch($hook);
         $output = $hook->get_output();
 
         $output .= $this->maintenance_warning();
@@ -885,8 +885,8 @@ public function standard_footer_html() {
         require_once(__DIR__ . '/classes/hook/output/before_standard_footer_html_generation.php');
 
         $hook = new before_standard_footer_html_generation($this);
-        di::get(hook_manager::class)->dispatch($hook);
         $hook->process_legacy_callbacks();
+        di::get(hook_manager::class)->dispatch($hook);
         $output = $hook->get_output();
 
         if ($this->page->devicetypeinuse == 'legacy') {
@@ -1122,8 +1122,8 @@ public function standard_after_main_region_html() {
             $hook->add_html($CFG->additionalhtmlbottomofbody);
         }
 
-        di::get(hook_manager::class)->dispatch($hook);
         $hook->process_legacy_callbacks();
+        di::get(hook_manager::class)->dispatch($hook);
 
         return $hook->get_output();
     }
@@ -1365,7 +1365,9 @@ public function header() {
         // TODO MDL-81134 Remove after LTS+1.
         require_once(__DIR__ . '/classes/hook/output/before_http_headers.php');
 
-        di::get(hook_manager::class)->dispatch(new before_http_headers($this));
+        $hook = new before_http_headers($this);
+        $hook->process_legacy_callbacks();
+        di::get(hook_manager::class)->dispatch($hook);
 
         if (\core\session\manager::is_loggedinas()) {
             $this->page->add_body_class('userloggedinas');
@@ -1489,8 +1491,8 @@ public function footer() {
         require_once(__DIR__ . '/classes/hook/output/before_footer_html_generation.php');
 
         $hook = new before_footer_html_generation($this);
-        di::get(hook_manager::class)->dispatch($hook);
         $hook->process_legacy_callbacks();
+        di::get(hook_manager::class)->dispatch($hook);
         $hook->add_html($this->container_end_all(true));
         $output = $hook->get_output();