The author did not realize that the "repetitive dictionary lookup" function is not a 1-to-1 mapping. There could be, for example, multiple words whose definition starts with "a type". All these words map to the same ciphertext, eventually.
The "repetitive dictionary lookup" function is very useful for validating Alice's claims of solving parts of the puzzle, but imperfect for deriving the solution from a ciphertext.
The "repetitive dictionary lookup" function is very useful for validating Alice's claims of solving parts of the puzzle, but imperfect for deriving the solution from a ciphertext.