I knew I read it somewhere, and it was in Mick Karn's autobiography. Don't want to start finding the page as someone already gave the answer in the other TB : https://www.talkbass.com/threads/when-did-mick-karn-switch-from-travis-bean-to-wal.833442/#post-11862761
You can tell your guitarist that he really is a guitarist : not reliable. 😁
From TB : In his autobiography, he states that while in the studio, extreme temperature changes were causing the aluminum neck to shift and not hold tune. It just so happened that the Wal factory was down the street from the studio. They let him borrow a bass to get through the session, and that was it.