Asking which U.S. president dies because of a volcano gives wrong answer.

Searching : "Which us president died because of a volcano?"

Gives the following answer:

Which is wrong because it confuses Harry R. Truman (businessman who famously died in a pyroclastic flow), and Harry S. Truman (U.S. president),

Something of the like:

No U.S. president died because of a volcano

It seems that the result already changed:

How is it possible?