Hey! This was actually my first critique here, so sorry to not have been clear enough. The thing is, the specific mistakes you made aren't that important. Everyone makes mistakes in this exercise and as you know the intersections aren't even the main focus of the exercise.

The problem is that it seems (at least to me) that some intersections were done hastily without fully considering the space. Why do I think this? Because most of the intersections are actually okay, but then some are very wrong. That's why more than pointing you out specific mistakes I told you to just be more careful. Because it should to the trick.

The intersectons will improve as you continue practing this exercise in your warmups. But if you want some exemples (I can't give you many because it's very difficult to refer to specific forms when the pages are full of them):

-Page 1: top box in the center. Any of its 3 intersections makes sense to me.

-Page 3: top right corner (box and cylinder).

-Page: bottom right corner. That cylinder and pyramid over the cube. And the fact that you messed up the lines in that pyramid kind of supports the idea that you should be taking more time and care with this exercise.

EDIT: typo