diff --git a/app/controllers/concerns/issue_templates_common.rb b/app/controllers/concerns/issue_templates_common.rb
index 2b50b1d6..62f33160 100644
--- a/app/controllers/concerns/issue_templates_common.rb
+++ b/app/controllers/concerns/issue_templates_common.rb
@@ -108,8 +108,12 @@ def core_fields_map_by_tracker_id(tracker_id: nil, project_id: nil)
       end
 
       if field == 'watcher_user_ids' && project_id.present?
-        issue = Issue.new(tracker_id: tracker_id, project_id: project_id)
-        watchers = helpers.users_for_new_issue_watchers(issue)
+        project_principals = if Watcher.reflections['user'].class_name == 'Principal'
+                               Project.find(project_id).principals.where(type: %w[User Group])
+                             else # Redmine 4.1.x or earlier
+                               Project.find(project_id).users
+                             end
+        watchers = project_principals.active.visible.sort
         value[:field_format] = 'list'
 
         value[:possible_values] = watchers.map { |user| "#{user.name} :#{user.id}" }
diff --git a/assets/javascripts/issue_templates.js b/assets/javascripts/issue_templates.js
index 983cce9d..b48b1ed8 100644
--- a/assets/javascripts/issue_templates.js
+++ b/assets/javascripts/issue_templates.js
@@ -423,13 +423,17 @@ ISSUE_TEMPLATE.prototype = {
     document.getElementById('issue_template').dispatchEvent(changeEvent)
   },
   checkSelectedWatchers: function (values) {
-    let targets = document.querySelectorAll('input[name="issue[watcher_user_ids][]"]')
-    for (let i = 0; i < targets.length; i++) {
-      let target = targets[i]
-      if (values.includes(target.value)) {
-        target.checked = true
-      }
-    }
+    // HACK: want to get this url and params in a stable way.
+    const rootPath = $('a.home').attr('href');
+    const projectPath = $('a.overview')?.attr('href') ?? `/projects/${$('#issue_project_id').val()}`;
+    const { projectId }  = /projects\/(?<projectId>.+)/.exec(projectPath).groups;
+    $.post({
+      url: `${rootPath}watchers/append.js`,
+      data: {
+        project_id: projectId,
+        watcher: { user_ids: values }
+      },
+    });
   },
   filterTemplate: function (event) {
     let cols = document.getElementsByClassName('template_data')