Its because of the 321neo... and I haven't heard a real/official explanation of why we can't pre-order on those either. In my opinion, the most plausible theories are:
- DL has a bug on their end that isn't recognizing or allowing pre order on this aircraft type.
- Insufficient galley configuration to accommodate more than 16 hot choices.
Although, with the second one I am curious what they do for dinner on a longer flight where all meal options are normally hot? Purposely load some cold trays and the last row to select loses out on anything edible?
Either way, its pretty poor that pre-ordering is still not available on this aircraft. And, its really crappy if you're sitting at the opposite end where they start taking orders and nothing is left for the last two rows but the nasty cold veg option.