Hmmm, maybe this is a new crackdown. I've had several tickets issued by AA (handwritten) and QF where the tax calc's were stapled to the ticket. In the case of QF the system couldn't print the whole calc. These tickets have been subsequently reissued by AA, BA, CX & QF with no problems. I'll be testing this soon with a reissue by BA in London for a QF ticket.