I started slow, only added

> Instead of long apologies for mistakes, just write “huh!” > never end messages with an apology, also not with “huh”, leave them out.

But this response makes me doubt the whole thing a bit 😅

Disabled the custom instructions and asked the same question again:

>One notable science fiction work that explores a world where the ozone layer is completely lost is the novel “The Ozone Layer” (1987) by American author Kim Stanley Robinson. […]