[I don't want to start a new thread for this because its largely a re-run of the OP's question and the responses it received]
I think I might have a similar conundrum. . . . .
Tomorrow, I'm travelling on a complex journey and picked up all the tickets from a TVM machine late this afternoon. I'd booked the journey via the excellent EC web site and collected 24 coupons/vouchers from the machine in Newcastle. (I even knelt down at the end of the process to check that I'd got them all, similar to a praying position!), then I re-sorted them into the journey's sequence before leaving.
Anyway, when I got back to the office, I noticed that the summary coupon which notes how many vouchers are printed in the transaction said 25, but I only counted 24 (incl the summary voucher).
Now I'm not going to bore you with what journey each of the 24 or 25 vouchers are for, but I really have been struggling to work out just which voucher could be missing. The serial numbers don't seem to help (which you'd think might reveal a gap in the number sequence, but they don't. And the first and last tickets are definitely present and correct.). But I do have a hunch that I know what could be missing - its in the middle of the journey (and therefore in the middle of the serial number sequence where there isn't a break) - and this is what puts me in the same position as the OP.
The relevant part of the journey is a return from Paddington to Bristol (PAD-BRI), with reservations. I have the seat reservations for each leg, but only one Return ticket, marked 'OUT' and also marked 'TWO PART RETURN'.
There isn't a corresponding 'RTN' voucher, but as I noted, then there isn't a gap in the ticket's serial numbers where it would appear.
So, my conundrum is, have I lost the ticket, or has 'the system' failed to print it (and failed to allocate a serial number to it)? There is a clue in that the TVM's display flashed a warning message in a window with a flasing red background that this journey was within a peak period for which it would be invalid, but which I believe is a restriction which does not apply to that leg of the actual journey).
Well, that's my story for tonight. I'll be starting my journey in the morning and will just have to see how I get on during the day with a 'missing' ticket.
And the point of this post? Its simply to keep the 'lost ticket' on FGW thread alive for a little longer!
I'll let you all know how I got on when I get back tomorrow night.