Was the original entropy case sensitive? The text should be converted to uppercase or lowercase before the computation.
As for the repetitions, they are expected even in a random text, just much less frequently compared to a natural plaintext. Here as you said, whenever the preceding ciphertext letter is the same, the same plaintext word would encode to the same ciphertext.
As for the repetitions, they are expected even in a random text, just much less frequently compared to a natural plaintext. Here as you said, whenever the preceding ciphertext letter is the same, the same plaintext word would encode to the same ciphertext.