In my most recent game I had a strange and frustrating experience with the one independent people on my home continent that didn't vanish or get conquered: As you can see from my screenshots I contributed more than 80% of the Cantabri's patronage, but the game was simultaneously convinced that I had no more than 50%, thus preventing my from signing a final treaty with them. I briefly stopped giving them any gold or influence, which lead to my miscalculated influence ticking down to 49%; it didn't get any higher when I resumed patronizing. I never had the opportunity to learn if this was peculiar to the Cantabri or if it would have happened with any independent people