If project doesn't have a group, group ldap sync is false.

app/models/project.rb

@@ -623,4 +623,12 @@ class Project < ActiveRecord::Base
   def origin_merge_requests
     merge_requests.where(source_project_id: self.id)
   end
+
+  def group_ldap_synced?
+    if group
+      group.ldap_synced?
+    else
+      false
+    end
+  end
 end

app/views/projects/team_members/_form.html.haml

@@ -12,7 +12,7 @@
   .form-group
     = f.label :user_ids, "People", class: 'control-label'
     .col-sm-10
-      = users_select_tag(:user_ids, { multiple: true, skip_ldap: @project.group.ldap_synced? })
+      = users_select_tag(:user_ids, { multiple: true, skip_ldap: @project.group_ldap_synced? })
 
   %p 2. Set access level for them
   .form-group