Yeah, 1, while the correct meaning of "determinism", is just not an interesting property. It's unfortunate that people use the word to mean 2.

2 is an interesting property and I agree that it's not possible for LLMs to possess it because it's a property of natural language itself, not the model. Not possessing it doesn't mean that LLMs can't be used to write software (obviously), but it does mean that using them isn't like using a compiler, which does have property 2. This is usually brought up in response to people claiming using LLMs is just another step in the process of increasing abstraction that led from punch cards to assembler to low level languages to high level languages*. That point stands: LLM use is qualitatively different to those steps because LLMs aren't "deterministic" in the sense of property 2.

There must be a better word for this, but I can't think of one right now.

* Even Linus Torvalds used that cockamamie framing just now: https://lore.kernel.org/lkml/CAHk-=whTs09_ozN+e09GU68N1wPP56...