this image is weird, like if it's being filtered

It's called Glaze. It's a noise pattern tool that's intended to confuse AI crawlers so they can't use (steal) the image.

Cool, thanks for answering

this glaze thingy is really visible even without zooming in. Not worth it if you ask me. I think pixiv is not obliged to keep your horny fantasies away from openai or any other tech corporation if they can get some money, and I'd say they rather do sell their datasets, ai is all the rage these days. And there's always the case of third parties which are not regulated at all.
here's ip ranges of open ai gptbot
52.230.152.0/24
52.233.106.0/24
and chatgpt-user
23.98.142.176/28
40.84.180.224/28
13.65.240.240/28
block them in your firewall in both directions.

as for the pic, anatomy left the chat on thi one