[LH2992] Compiling EPUB - Index wrong when styles applied to sections with titles

I compiled anovel with default settings. The result had no titles to parts, chapters and scenes but the index showed as expected. When I applied styles to the section types which have titles and compiled again, the titles appeared (I look forward to being able to change their appearance) but the index had ‘UNKNOWN’ for all entries except one (deliberately) orphaned scene with no title.

Thanks this has been filed.