Steps to reproduce:
1. Create a custom doctype with both Folderish and Collection facets by extending Folder doctype and marking "Document is a Collection" (named "CustomFolder" in local testing). In JSON export facets should look like the following:
2. In Web UI, create an instance of CustomFolder and enable Drive sync by clicking nuxeo-drive-sync-toggle-button from Document actions bar in top-right
3. Add sub-folders / content inside this folder using Create/Import
4. Verify the CustomFolder and its contents appear in local directory
5. Unsynchronize this folder from Web UI; verify the folder disappears from local
6. Add various sub-folders / content to the CustomFolder instance
7. Synchronize the CustomFolder again using nuxeo-drive-sync-toggle-button
After re-synchronizing the CustomFolder, the folder and its nested contents reappear in the local Drive sync directory.
The CustomFolder reappears in the local Drive sync directory, but its contents are empty (any content added from Web UI after re-syncing successfully appears in local).