[McAroni]

So, indeed, everything's fine when I already have my file copied before starting the import process.

I always bring the files to the device first before importing. Sometimes msp does some strange things regarding moving Files to the right place.
I manage my file structure via an folder sync app. If the files are at the right place before importing everything works fine.
If the folder structure does not matter then you will not even recognize if there are the files sometimes not on the right place. Everything still works fine.
But for me it is important, so i do the sync of the files folder my own way.