Found a strange diplomacy bug, playing as the Entente, the CP influenced Spain all the way up to 23(military support in favour of Central Powers). As expected, I had to garrison Toulouse, no problems there. But strangely I also got the economic aid and RP treaties from Spain, which is only supposed to happen if the Spanish diplomatic level is in favor of the Entente(level 10).
Had the same in a game with the CP, with Spain signing the secret treaty with France even although the diplomatic level was in my favour.