You seem to be saying that the gameworld is inconsistent anytime the game-mechanical likelihoods of some outcome do not correspond to the ingame causal probabilities.It may be a metagame term, but that doesn't mean it's effects are unobservable by the PCs. If you give a monster a +1 AC without granting the PCs an offsetting +1 Attack, you've changed the world in a measurable way. You made something harder to hit. It's different. Ergo, your game world is inconsistent if you did that for a reason that maps to the story you're telling rather than an "in game" cause & effect.
Like, for instance, if you promoted a city guard from 3rd level soldier to 10th level minion just so your players could have a fight with a little risk in it. His Attacks and AC are higher. A 1st level PC would have great trouble hitting his AC. The world is inconsistent.
On this notion of consistency, any game with a Fate Point mechanic, or with a mechanic such as TRoS's Spiritual Attributes or HeroWars's Relationships delivers an inconsistent gameworld.
Needless to say, I don't accept that the gameworld is inconsistent anytime the game-mechanial likelihoods of some outcome do not correspond to the ingame causal probabilities. For example, the game-mechanical likelihood of an PC in my game dying from a heart attack on the toilet, or from falling out of bed after waking up in the morning is zero. That does not correspond to the ingame causal probabilities which, I assume, are the same as in the real world. It doesn't follow that the gameworld is inconsistent. Rather, for metagame reasons (eg thematic significance) certain things that are possible in the gameworld never actually happen.