Steps to reproduce
1. Create a document on a Mac client that is stored in a wrapper/package (which actually is a folder) - e.g. in TextEdit create a formatted text with images (file format rtfd).
2. Sync it
3. Make different changes on two Mac clients while offline -> sync conflict
There should be two documents, meaning two version of the whole wrapper.
Inside the wrapper (folder) only some specific files are duplicated as a result of the conflict. The users on both clients do not even recognize a conflict, as they normally do not see the contents of the wrapper. The conflict files are ignored by the application editing the document as they are not considered part of the document structure.
Only if you look inside a wrapper (which on the Mac can only be done via a not well known context menu command or command line) the conflict files are revealed.
A user has no way if resolving the conflict as he/she cannot know which files in the wrapper to combine to get a working version of the document.