By default, Assembler will not generate an ID for a section title that was created from a text-only nav entry. Instead, it forcefully deactivates sectids for that section title. Turning of the ID for a section title breaks the entry in the TOC in the HTML and EPUB output formats. Although it's possible for the user to force a synthetic ID to be generated by setting `sectids` attribute in the Assembler configuration, this should not be necessary. Instead, Assembler should always generate an ID for these section titles. The ID should be the value that Asciidoctor auto-generates followed by `-tid-` followed by the object ID of the nav entry (e.g., `category-tid-3923748`). That will guarantee that the ID is unique while still making it readable.