Perhaps it's just a bias? You are already negatively biased against LLM writing so you disregard stuff you read when you suspect it's an LLM. This could also be a selection bias. It may be that you generally struggled to retain information but you are more aware of it when LLMs are involved.

I don't think so, no, because it extends to LLM-generated text I want to recall.

I use LLMs to generate starter/tutorial material. I may hate the way Claude writes but I absolutely don't hate the way Gemma 4 writes. But I have to continuously consult it in a way that I do not with human-written text, which gets its message across in a more persistent way I find less troubling.

(This non-memorability extends to AI images and video.)

You are right that there are some confounding factors in my life but while I was worried about middle age affecting recall, I find actually I am still remembering stuff humans wrote pretty much fine.

ETA: there is one thing that I have noticed that does affect recall that is specific to LLMs: watching text roll out word-by-word in LLM chat, I think, damages recall. It's engaging the wrong kind of memory and focus.

So I now let it generate and I'm trying to find decent ways to format it e.g. as PDF, to give it the best chance.

This could be generational; there were many studies twenty years ago that suggest that people a decade or so younger than me who grew up with full colour books and magazines and multimedia can read less-linear text layouts more comfortably, for example, so it's not out of the question that there's something generational going on here too.