Board Thread:Support Requests - Getting Technical/@comment-1853435-20160621015122/@comment-24473195-20160625163745

You can overcome the issue by using a template and parser function e.g.

{{#if:namespace|add category.

Alternatively you can use safesubt by making  it return empty contents if it is not the right namespace or a category if it is.

Anyway, you can report it as a bug as I'm not really sure anyone has reported it yet.