diff --git a/course/format/classes/output/local/content/cm.php b/course/format/classes/output/local/content/cm.php
index 03473e53144..76173d173b8 100644
--- a/course/format/classes/output/local/content/cm.php
+++ b/course/format/classes/output/local/content/cm.php
@@ -122,6 +122,7 @@ class cm implements named_templatable, renderable {
             'classlist' => [],
             'cmid' => $mod->id,
             'editing' => $PAGE->user_is_editing(),
+            'sectionnum' => $this->section->section,
         ];
 
         // Add partial data segments.
diff --git a/course/templates/activitychooserbuttonactivity.mustache b/course/templates/activitychooserbuttonactivity.mustache
index bfdd774c75b..d72eacbb704 100644
--- a/course/templates/activitychooserbuttonactivity.mustache
+++ b/course/templates/activitychooserbuttonactivity.mustache
@@ -27,13 +27,13 @@
     Example context (json):
     {
         "id": 0,
-        "num": 1,
+        "sectionnum": 1,
         "sectionreturn": 5
     }
 }}
 <button class="btn add-content section-modchooser section-modchooser-link activitychooser-button d-flex justify-content-center align-items-center p-1 icon-no-margin"
         data-action="open-chooser"
-        data-sectionid="{{num}}"
+        data-sectionid="{{sectionnum}}"
         {{#sectionreturn}}data-sectionreturnid="{{.}}"{{/sectionreturn}}
         data-beforemod="{{id}}"
         aria-label="{{#str}}insertresourceoractivitybefore, core, { "activityname": {{#quote}} {{activityname}} {{/quote}} } {{/str}}"