Sonnet was not trained with this information and extremely-recent-information-without-access-to-a-Web-Search-tool is the core case of hallucination.

Sonnet does have search available FYI.

LLMs are lazy about using Search unless explicitly prompted to do so (either explicitly or by implying it with phrases such as "recent").

In the OP's case, there is no motivation for the LLM to perform a Search.