Yes, I had a related experience of reading a book and observing what I thought were claude-isms, only to realize it was written in 2019. Some of the common tells are actually good writing practices, but I guess they are best in smaller doses.
The LLMs haven't invented anything. Every LLM-ism is some pre-existing and established word, metaphor, and or stylistic element mechanically overused until it becomes an instant cliche.
The other LLM-ism is vapid bullshit: meaningless crap that's kind of like those old hollywood facades: it appears to be a substantial building, but if you look a bit closer it's just a single wall propped up (https://www.ferrovial.com/blog/en/2018/03/the-fake-architect...).
But the LLMs really seem to fixate on using the same ones in the same places all the time. I guess that's because that's the highest probability construction.
Most of us are only dealing with a handful of hyper-productive LLMs, so it makes sense that the LLM-ticks get old much quicker.
[0]: https://slate.com/human-interest/2011/05/em-dashes-why-write...
as I see them they are all truly terrible even if authored by humans
Only mentioning because your "actually" may imply you thought you were disagreeing, when in fact it's one big happy family!
Or do you mean that the patterns that AI is showing today were already present in communication around that time?
That seems obvious as well, as AI has a lot of repetitive patterns that come from all kinds of periods, of which “load-bearing” is just one.