For the duplicate ID part:
Somehow this line https://github.com/xwiki/xwiki-platform/blob/6a7f19f6424036fce3d703413137adde950ae809/xwiki-platform-core/xwiki-platform-search/xwiki-platform-search-ui/src/main/resources/XWiki/SearchSuggestSourceSheet.xml#L60 produces different outputs when used in the template for highlight and activated. It might be because there's an overlap in the names of the Config / SuggestSource properties...