I have a full passenger list and frequently acquire an excess of colonial passengers through repeating the Resettle Colonists duty officer mission (it gives my duty officers something to do when my In Progress total is lower than 20). However, while the Resettle mission reappears constantly, colonization assignment chain missions have not appeared at all since I began playing again a few weeks ago, and I check in every few hours to see how my duty officers are doing.
My specific focus right now is on the "Colonization of the Arucanis Arm" assignment chain, so I have tried hanging out in the Celes Sector Block and inside the Arucanis Arm itself, both for extended periods of time so that I would not miss an update of the mission list by switching from one to the other too quickly.
Investigating the STO wiki on gamepedia.com, I did not learn any specific details that help my understanding of the situation.
Are there any triggers that cause the colonization assignment chain mission to appear in the Duty Officer mission list? Or, are there any triggers that cause the mission to not show up?