multilayer EXR taking 1050 seconds to preview (or failing to) only on one computer/project

On any other PC it's the usual 2 seconds per frame, and on this PC other exr sequences, in the same folder, with the same kind of content, also takes a few seconds. The only difference is that I have 3 image sequence instead of the usual 2. I've been trying to diagnose it for a week, but it feels like a bug, it's been gradual the more I opened and saved Ae files, each of them renders slower from 1000 seconds, to no render happening. There's nothing special with the images as they render just fine on another machine. Tried everything with cache obviously first ect..
If I import these images, they render, until I import the third sequence, a cryptomatte, where it stops working, but it still doesn't work after it's deleted from the file too.