Update:
My collegue had accidentally placed a skybox texture referenced by the persistant map in the local engine folder (not in source control). This possibly had nothing to do with it as it was two sublevels that could not be opened, but worth mentioning.
Another, more important thing is that the migration worked because that project had no virtual textures activated. Setting “Enable virtual textures for anisotropic filtering” to false fixes the crash on my end. But it’s curious that my collegue doesn’t experience the problem with it activated.