I've seen cock-ups like this happen before. Detailed fabrication drawings are auto-generated paper documents (paper, because each one must be signed and stamped by the stress engineer and signed by the checker and because paper is easier to handle by the fabrication shop and remains the copy of record).
Sometimes, but rarely, a minor change is made in the 3D model and a new physical drawing is not printed and sent through the document process. In this case, the 3D model is correct but the detailed drawing is not. Or the reverse can happen; the detailed drawing is manually edited (say, under pressure to meet a deadline, with the intent to update the model as soon as the rush is over - then someone forgets) leaving the model incorrect.
