To answer your question, I've never had it happen to me, but I don't write such complicated pieces, rather, I write simple songs.
Even so, I always, always bounce down the song to another track in the project so I can compare and ensure it's how I want it. You discovered the error by listening to it, right?
I imagine it would make a person look bad if the work wasn't what the client asked for or is missing a detail that was required. Anyway, my comment above was about making sure it was ready before shipment.
Maybe report this to Cakewalk staff directly if you haven't already done so. Good luck!