A transposition pattern is a major identifying feature of a common technology base. For one broad example, consider books from a library. Many features of books are transposed from one to another, for example indexes, page numbers, tables of contents, photographs, formulas, footnotes, paragraphs, sentences, words, and grammar. These interlinking features show that the books are from a common civilization. Yet the books are the product of multiple designers working independently with no common goal.
Widespread transposition is a major indication that nothing out of the ordinary is happening.
In summary, a transposition pattern would not look like a message, nor would it unambiguously look like the product of a single designer. It would not meet the requirements of the biotic message. This is a second reason why a transposition pattern should be avoided by a biomessage sender.