Android : ENOENT error with Sync by File system

I have ran into an issue quite similar as described in

My situation is the following:
(android-8.0.0, Joplin-1.0.305)

On my phone I have a company internal sync folder based on MyBox. I now try to make Joplin sync via the file system and in particular a sub-folder in that already synced folder.

If I choose any other local directory as sync folder on android with a clean installation, it works and the usual set of files is being created in the given directory.

If I choose a not yet existing sub-folder in the MyBox sync folder, the sub-folder is correctly being created and I also can find the .resource and .sync sub-directories in there. However there aren't any files. When trying to sync from within Joplin I receive an ENOENT error

09-17T07:51:24,30,"""RevisionService::maintenance: Done in 404ms""
09-17T07:51:24,30,"""RevisionService::collectRevisions: Created revisions for 0 notes""
09-17T07:51:24,30,"""RevisionService::maintenance: Service is enabled""
09-17T07:51:24,30,"""RevisionService::maintenance: Starting...""
09-17T07:50:20,30,"""RevisionService::maintenance: Done in 969ms""
09-17T07:50:20,30,"""RevisionService::collectRevisions: Created revisions for 0 notes""
09-17T07:50:19,30,"""RevisionService::maintenance: Service is enabled""
09-17T07:50:19,30,"""RevisionService::maintenance: Starting...""
09-17T07:49:47,30,"""RevisionService::maintenance: Done in 4273ms""
09-17T07:49:47,30,"""RevisionService::collectRevisions: Created revisions for 0 notes""
09-17T07:49:43,30,"""RevisionService::maintenance: Service is enabled""
09-17T07:49:43,30,"""RevisionService::maintenance: Starting...""
09-17T07:49:11,30,"""Total notes: 1""
09-17T07:49:11,30,"""Total resources: 0""
09-17T07:49:11,20,"""There was some errors:""
09-17T07:49:11,20,"""Error: Error: ENOENT: no such file or directory, open '/storage/emulated/0/MyBox/'. Path: /storage/emulated/0/MyBox/
callImmediates@[native code]
value@[native code]
value@[native code]""
09-17T07:49:11,30,"""Total folders: 1""
09-17T07:49:11,30,"""RevisionService::maintenance: Done in 173ms""
09-17T07:49:11,30,"""RevisionService::collectRevisions: Created revisions for 0 notes""
09-17T07:49:11,30,"""Operations completed: ""
09-17T07:49:11,30,"""createRemote: 1""
09-17T07:49:11,10,"""Error: Error: ENOENT: no such file or directory, open '/storage/emulated/0/MyBox/'. Path: /storage/emulated/0/MyBox/

If I first create a joplin sync folder in the MyBox area using a PC client of Joplin, then I still see exactly the same error message on Android i.e. the file name mentioned in the ENOENT error message on Android is not one of the existing file names in the sync folder.

Any clever advice how to proceed?