29 hotels have category 0, which has no label. The product teasers looked the label up unguarded, an "Undefined array key 0" warning: a 500 in DDEV (warnings are exceptions there), a logged warning in production. The teaser and the hotel serializer now use null for an unknown category, as SearchResultService and HotelDataService already do; TYPO3 10 ended up with null as well. Co-Authored-By: Claude Opus 5.5 <[email protected]>