Shapes / edges distortion

I've handed over my design files for preprint, but as you can see in the before/after screenshots, the designs appear distorted when opened by another designer, edges are misaligned, and lines don't match up.

I remember encountering a similar issue a few years ago, and it was resolved by a single setting or adjustment in Illustrator, but I can't recall what it was. Could you please advise on what might be causing this and how to fix it?

Thanks for your help!