Posted a whole story in screenshots, all 7 images in one album in Imgur: https://imgur.com/a/zjJ1iFW
There is fluid ideology, with Supremacy, Tunneler, Human primacy. Precepts for "corpses:don't care", "small spaces:don't care", Shooting and Crafting specialists. Shown on first and second screenshot. Because of chosen memes, all this precepts and roles are allowed, 100% valid ideoligion.
Choose to reform ideoligion, add collectivist (screenshot 3).
A message that Small spaces, Corpses, Production and shooting specialists are incompatible appears, screenshot 4.
According to displayed message, precepts and roles are removed. Screenshot 6 shows, that I can add small spaces: don't care precept.
Screenshot 7 show that I can add Shooting and Production specialists again.
What makes this annoying is that player has to assign all specialists to their former roles again after such reform. In a large colony, that's not too easy, considering each re-assignment needs rather many spectators.
There are pawns of non-main ideology in colony, 2 believers of Ancients ideology and 3 guys each of whom believes in different major non-player faction ideoligion.