InCopy Crashes immediately after opening a shared InDesign file on network

Maybe someone can help solve a problem someone on our magazine production team is having. An editor using InCopy for collaborative work opens an InDesign file and IC crashes immediately. It's vexing because it doesn't happen for her with other files nor with other team members opening the "problem" file. We have eliminated other obvious culprits, everyone is running IC/ID 2018 v13.1 and the designer and editor in question are working on on Macs with Sierra 10.12.6, 16MG. We all access shared files on our network. The editor having this IC crash problem has no issue when working on other ID files. One temporary fix seems to be if the Designer opens the ID file and resaves it, the editor can then use IC to open that ID file wo crashing. But this step must be repeated again and again. It's a pain and confusing.

We think it may have to do with something in the specific InDesign file we use for that column but don't really know what that might be since other editors are not having the same crash problem.

Claudia