Plugin breaks author archive if author has no posts

If an author has no posts, yet you go to their author archive permalink, you normally see a message like (from twentyfourteen): “Apologies, but no results were found for the requested archive. Perhaps searching will help find a related post.”

However, with 404page active in compatibility mode (because the site is using Siteorigin Page Builder), because the plugin filters posts_results and returns the page assigned to the special 404 page, this fools the author archive template into thinking that the requested author actually has one post published.

https://www.ads-software.com/plugins/404page/