In the future, when you're curious about what a function is doing, you can go right to the source. In this case, perldoc -tf die says:

            If the last element of LIST does not end in a newline, the
            current script line number and input line number (if any) 
+are
            also printed, and a newline is supplied. Note that the "in
+put
            line number" (also known as "chunk") is subject to whateve
+r
            notion of "line" happens to be currently in effect, and is
+ also
            available as the special variable $.. See "$/" in perlvar 
+and
            "$." in perlvar.
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I think that says pretty clearly that the behavior is expected, and how to alter the behavior.