When <embed> entries are used to bring in a section, the heading in that section has to be turned from level 1 to level 2, as level 1 is for page titles.
Example File - /text/swriter/main0101.xhp
Syntax - <embed href="text/shared/01/01010000.xhp#neu"/>
Wikihelp URL - https://help.libreoffice.org/Writer/File
Notice that New comes in as "= [[Common/New|New]] =" while the non embedded Open comes is "== [[Common/Open_1|Open]] ==".
Seems my work to fix the menus has fixed the issue at < https://help.libreoffice.org/Writer/File >, but the issue can still be seen at < https://help.libreoffice.org/Writer/Table > as '== [[Writer/AutoFormat_for_Tables|Table AutoFormat]] ==' should have been '= [[Writer/AutoFormat_for_Tables|Table AutoFormat]] ='.
The issue also applies to the new online help. Dependency set.
Olivier Hallot committed a patch related to this issue.
It has been pushed to "master":
tdf#94017 embeded h1 entries should be h2