Oh for the love of god, internal consistency is about the plot in a work of fiction following the rules set by the author. By your definition, fantasy can never be internally consistent, which is absolute bollocks
Apart from math, which is a purely formal system of inference, coming up with internally consistent systems is an absurd and impossible proposition. The single most important set of rules IRL - the law - isn't an internally consistent system. And this is a system that decides the lives of billions of people, that is constantly refined and revised by hundreds of brilliant people daily.
Asking a single person to come up with an internally consistent system of rules to govern the operation of an entire fake reality is insane.
Authors try to come up with reasonable and plausible fake rules, and apply them in reasonable and plausible ways. People will sometimes disagree on whether this makes sense. But talking about it as a matter of consistency is stupid, because internal consistency isn't even a worthwhile aim in most cases, and is almost certainly impossible to achieve outside of very formal systems of inference.
Fantasy is absolutely not internally consistent. Most often, it doesn't even have clear rules.
I'm not talking about maintaining consistency with known science. I'm talking about maintaining consistency with it's own lore. Which a good writer can absolutely do just by making continuity checks.
If you don't like that trope, then try Magic A is Magic A
First off, in ME, "it's own lore" is an idiotic pastiche of actual science and incoherent gibberish. "Element zero" tries to come actual concepts in physics - mass and gravity, and especially atomic number - and builds on that a mind-bendingly stupid justification that's basically magic for why super space neutrons allow for FTL. No implications from this are explored, and the writers don't even have the knowledge or capacity to explore them. They're asking themselves to create thought experiments based on modifying the fundamental rules of reality and then predicting how - in this modified world - bodies would react. This is an insane proposition. Quarian immunology is another dumb concept.
And the opposite concept - and entirely logically consistent idea, but one that obviously contradicts IRL science - the human genetic diversity point gets lambasted all the time on this forum.
So they just make this **** up in a way that tells a good story. Some of the time it's plausible, often it's nonsense, and how close to nonsense it is depends on how ignorant the writer is and how knowledgeable the player is in contrast.
But talking about consistency is just a vacuous talking point. People want stories to seem reasonable and plausible to them. That's fine. But dressing this up as being about some greater principle of logic, in the formal sense, is silly, because it's not.