How perfect is Voynichese?

[pfeaster]

What are some historical examples of a "corrupted cipher"?
Codex Copiale (but here, rather, an example of a complicated substitution with the addition of zeros) and You are not allowed to view links. Register or Login to view. (still not deciphered, but it is believed that this is a complicated Polybius square).

Here are a couple particularly messed-up examples from the early seventeenth century, with an analysis of what went wrong (only possible because we know what the texts "should" say):

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