Build fails on JRuby for files that contain only front matter

Build fails on JRuby for files that contain only front matter: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). I'm building a site with Awestruct on JRuby. A few of my pages are placeholders — they have a YAML front matter header (title, layout, some metadata) but…