If a spell is supposed to do X, but does Y instead, you already know it's broken.
The question is - how one does know what the spell "is supposed to do" and "what it does instead".
It also doesn't change the fact that everyone and their mother observed
I've seen only 1 such observation so far, from
InD_ImaginE . Probably, you've seen more. It does not change the fact that we're comparing our personal experience and nothing more.
Oh, and what do you mean by "source code"? It's a Unity game - everyone can fiddle with the game, if they have enough technical skills.
Have you ever seen what is shown by dnSpy? Have you compared it with proper C# code? It might be enough to "fiddle", but not enough to understand design and architecture of the game.
It is obvious that Kingmaker's code is brittle. The last article about turn base mode implementation and the article for WotR Kickstarter about the changes in the program structure have indirect, but compelling evidence of it. The fact that Owlcats cannot change their code reliably and have to fix it every time is direct evidence.
However, using the words of a mod author to discuss the architecture of a program is like using a faith healer when your mother has breast cancer.