Hi @Sick^ ,
The default behavior gives a white screen for a 404 page not found when there is no error redirect.. i always tought i i had script issue since nothing came on screen, but it seems to be 'feature'.... maybe hold on to the default behavior untill somebody changes that setting.
Also, i wonder if you are still maintaining this addon? I reported a bug months ago and since then nothing has changed and people are reporting issues with the sitemap part(memory hungry)...