I disagree. While the use of the word 'bug' is often stretched (i.e. feature requests being made in the issue tracker), the contracts in this case are not purely the product of a writer - they are also a contract, as in a written, explicit agreement. Calling an unintended consequence a bug may be true from the perceptive of the writer, but not necessarily from the perspective of the second-party, who may have agreed to the written contract, but not the "intent". Hence a document with two parties does not have objective bugs in that sense, unless both parties agree, which is not the case in disputes requiring a judge.