well, oceanrider,
seems you really have special luck with LX and carry on.
on my IST-ZRH-MUC flight in Y I had no problems. at check-in in IST they looked at my bigger bag and weighted it. had almost 10kg and is slightly above size limits, but no problem, i got the carry-on "sticker". and i had a notebook bag as well. (flight was ~80% full)
but good luck to you for future trips.