Culture flip question re disappearing % in rebellion

Posted on Saturday, September 3, 2016

I'm around turn 60 of a 1.82 game with Mercenaries and most DLC active, no mods.

A few turns ago my friendly-but-pushy neigbours, United Earth, had a couple of colonies in my influence space that were in partial rebellion, one at 49% and the other in the mid-20s.

When I looked just now, they had both went to 0%. The endoskeletal twits have another colony in a different part of my turf that is still in increasing rebellion.

Is there some improvement I haven't learned that isn't well-described in the wiki that could be emulating the Unwavering species ability or the Undaunted ideology ability?