I have recently experienced this on CX139. The menu states “Dinner - served midway through your flight”.

I asked the ISM about this when she was taking my order at the beginning of the flight and she said that yes they will serve it around 2 hours after the first service. She said it’s because people start getting hungry at this stage. Also this sector doesn’t have any “snack meals”.

I mentioned it’s probably a bit early for me so she was happy to hold the meal and serve it to me later. But she was an excellent ISM. I’m not sure if others would be so accommodating.