404 error when viewing a single system hook

I'm not sure if this should be even viewable.

Steps to reproduce

1. Visit http://localhost:3000/admin/hooks
2. Add a new system hook
3. Click on hook URL in the table of hooks
4. 404

A strange thing in the log is that the call gets captured twice, not sure it's worth mentioning.

Started GET "/admin/hooks/4" for 127.0.0.1 at 2016-01-24 19:56:19 +0100
Processing by NamespacesController#show as HTML
  Parameters: {"id"=>"admin/hooks/4"}
  User Load (0.3ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1  ORDER BY "users"."id" DESC LIMIT 1  [["id", 28]]
  ActiveRecord::SchemaMigration Load (0.3ms)  SELECT "schema_migrations".* FROM "schema_migrations"
   (0.1ms)  BEGIN
   (0.1ms)  ROLLBACK
  Namespace Load (0.3ms)  SELECT  "namespaces".* FROM "namespaces" WHERE "namespaces"."path" = $1  ORDER BY "namespaces"."id" DESC LIMIT 1  [["path", "admin/hooks/4"]]
  Rendered public/404.html (0.1ms)
Completed 404 Not Found in 43ms (Views: 3.3ms | ActiveRecord: 2.2ms)


Started GET "/admin/hooks/4" for 127.0.0.1 at 2016-01-24 19:56:19 +0100
Processing by NamespacesController#show as HTML
  Parameters: {"id"=>"admin/hooks/4"}
  User Load (0.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1  ORDER BY "users"."id" DESC LIMIT 1  [["id", 28]]
  ActiveRecord::SchemaMigration Load (0.2ms)  SELECT "schema_migrations".* FROM "schema_migrations"
   (0.1ms)  BEGIN
   (0.1ms)  ROLLBACK
  Namespace Load (0.3ms)  SELECT  "namespaces".* FROM "namespaces" WHERE "namespaces"."path" = $1  ORDER BY "namespaces"."id" DESC LIMIT 1  [["path", "admin/hooks/4"]]
  Rendered public/404.html (0.1ms)
Completed 404 Not Found in 42ms (Views: 2.3ms | ActiveRecord: 2.2ms)