I don’t know if any of you will remember SWA cable where the insulated cores were bound together with a wide two layer tape and then the armouring laid over this. An extruded outer sheath overall.
As an apprentice I was making off one of these cables (70mm) and everything was going well, went to make off the other end and the inner serving wasn’t taped but extruded? We’d got the foreman, charge hand, tradesman and myself all scratching our heads. Every test we did said it was the correct cable at each end. In the end the decision was made rip it out!
Later I stripped it down, half way along the length I found where the manufactures had swapped form one form to the other.
BICC (I think, it’s a long time back) had supplied the cable were most apologetic it had escaped their system.
It went in to the Christmas fund.