Why does format happen after read in this example from Paul Graham Book

Question

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Lisp format and force-output

I'm reading Paul Grahams book ANSI common lisp and on page 19 (haven't gotten far yet) there is an example that I tried in sbcl.

(defun askem (string)
  (format t "~A" string)
  (read))

When I run it in REPL, I have to input something before the prompt is printed. If I save the file and do

(load "test.lisp") 
(askem "test> ")

the same occurs Any reason why?