Direct answer
Objectives follow journal display order. Some depend on your choices; follow the active objective in the game.
Result
Those who stray off the beaten tracks in the bogs of Velen rarely live to amend their error. Even the Nilfgaardian soldiers stationed at the Army Group 'Center' camp would at times disappear in the marshes without a trace. After yet another patrol failed to return, the quartermaster of the camp posted a call for some brave soul to search them out and bring them back, or, barring that, at least determine their fate.
