Adopted Internal SD Card is mounted twice

I've adopted my external SD card as internal storage with the new feature of Android 6.0 (Samsung Galaxy S4 Mini with CyanogenMod 13). Since I've done this I've recognized that my stock image galery app and music player (stock and every other I've tried) lists every media file on the external SD card twice.

I know that these media files (pictures, music,...) aren't really duplicates because if I remove one file, the "copy" is deleted too. If I add new files it gets "duplicated" as well.

So I've tried to figure out the problem. I've noticed that the content of my external SD card is mounted under /sdcard/ with a symbolic link:

$ ls -la | grep "\->"

lrwxrwxrwx
1 root
root

 21 2016-07-11 10:07 sdcard -> /storage/self/primary

And under /storage/emulated/0/ (I can't execute the ls command in /storage/emulated/) which has exactly the same files and folders.

So is there any way to remove one of these mount points safely (I don't know which App uses which of these folders...)? Or is there any other way to tell the media library to only scan one of these directories?