Titles.adoc:27: 'Title level 2 short' seems to be a two-lines title underlined with '~', but the underlines are too short or too long compared to the title length. You may want to fix your master document.
Titles.adoc:30: 'Title level 2 long' seems to be a two-lines title underlined with '~', but the underlines are too short or too long compared to the title length. You may want to fix your master document.