The recalled Astute module wiring error

Was a submarine module built the wrong way round?

The account is clarified as a wiring-orientation problem while a module was assembled upside down. It is a recollection, with the fourth Astute boat suggested tentatively.

The initial recollection is that a module was built upside down and not turned over. The later clarification concerns wiring diagrams supplied for a module being assembled upside down to make access easier. A changed diagram supposedly failed to account for that orientation, so the wiring was laid out incorrectly. The error is said to have been discovered only after completion of the module. The account is presented from memory and hearsay, including the tentative identification of the fourth Astute-class boat.