I've already beat the game but my 4th echelon missions are at 63%. There is 1 grim mission I haven't finished and the coop only missions. I haven't beat any gone dark missions either.
So two questions... 1. What triggers these and 2. Will they reappear if you fail one?
They are set at random and appears for 2 days I think? If you don't get, it will disappear and another will reappear in a day. If you get them right, you get a .5 bonus, so that means extra cash which is good unless you have all the upgrades. Some are easy, just look for a keyword or phrase that you can easily google unless you know it already. I have a site that will give you all the answers if you want unless you want to figure them out on your own.
"Fools set the rules in this world. Just take a look around. It's undeniable." -Noctis Lucis Caelum - Final Fantasy XV
they appear daily. I think.
They are just missions where you have to pinpoint some areas in the map. It's not an actual mission.
you locate the next area in the map using clues from the first report. Ex. blah blah blah East Coast.
until you get to the 4th and last one where you have to choose using the analog stick and X. You have to pick the right one though or it will fail and you can't retry until they appear again...
they give you a 0.5 modifier in money earnings which is nice if you just started. But if you got everything already...don't bother with this.