it's self evident isn't it - such a consciousness has never existed, one existing would be by the fact of existing be weird

It doesn't seem self evident to me, no.

I suspect the reasoning is connected to free will vs. determinism. But no, I see no inconsistency. You'll have to actually point it out.

The problem is that science has found no evidence of free will, leaving humans to be nothing except determinism and chance (and given that QM effects don't scale to molecular level, that leaves only determinism). The oddity in conscious LLMs wouldn't be the determinism, it would be that we finally have a consciousness running on a system we have enough control over to repeat the same state.