Do not call formatTime which will return a localized time format (based on the translation setting of the user) which then fails to match the (English language) $translatable characters defined in PhutilTranslator.php, throwing a search exception when calendar items match the search query string.

Also update DateTime exception handling comment per changes in PHP 8.3:
https://www.php.net/manual/en/class.datemalformedstringexception.php

EXCEPTION: (PhutilAggregateException) All of the configured Fulltext Search services failed.
    - DateMalformedStringException: Failed to parse time string (2024-05-04 12:00 epp.) at position 17 (e): The timezone could not be found in the database at [<phorge>/src/infrastructure/cluster/search/PhabricatorSearchService.php:276]

Closes T15811

Please follow the verbose steps in T15811. In short: Install the Translations extension, set your language to a language which translated AM/PM in time strings, create a calendar event, use the global search to search for the calendar event title.