Dupes run to weird distent corner to eat.

I think it's expected. They try to eat in a place with enough oxygen.

You're missing tables and they going for the place with the nicest temperature. On my first Ceres run I had quite early an open polluted water vent. Dinner was inside the polluted oxygen it created.

There's plenty of oxygen where they got the food. it's right next to the Deffusers. 

After reloaded they picked a different spot. There's o2 there, but they had to traverse a shaft of co2 to get to it.