(There wasn't a bug report option for the piece of data I actually wanted to report) When I make custom ideologies, and set my mod as an ideological overhaul, I can change the government of the country to any of those ideologies, but I cannot make political parties of those types, only four display, and they only display if they share a name with a game's ideologies. This prevents making custom parties and adjustments to the game.
Cheesecurds
https://edge.hoi4modding.com/focus-tree/edit/98265