When you import and export JSON-LD files directly from openLCA and directly into openLCA there should be no issues between Windows and MacOS because the architecture of the file is the same (better use the same openLCA version). If there is still an issue, please let us know the details (openLCA version, Windows version, MacOS version, a step-by-step guide to reproduce the issue, maybe sharing the JSON-LD file ...).
However, there is problems from the MacOS system when you create your own zip-file with the MacOS build-in archive tool, or when you unzip and recreate a JSON-LD file manually with the MacOS build-in archive tool, outside of openLCA. The problem is that MacOS is adding special data (resources) to their zip-files, which can make the file unreadable/corrupted for some software. When you want to create your own zip-files with an archive tool from the operating system outside of openLCA, you can use for example Keka (open source) on MacOS which is excluding these system resources/data in the zip-files. Windows does not have these system resources/data in their build-in zip tool.