When you spend turns and you run out of food, it says military is sold to makeup for the short fall. How does the process work?

Is it all private market sales? And then private market purchase of bushels? Basically ensuring the worse possible deal for you leading to large networth drop?

Which unit type do they sell automatically? Is it even across all unit types? Do they buy based on net food production short fall? Or do they buy more than you need?

This usually happens when exploring or cashing or researching something like 50 turns in one go.

something like 5% of your military is lost

more like 10%.

unless express has its own quirk then your military ain't sold when you ran out of food, part of your military just abandons your country.

Ouch!