Most devices, including iBasso, do not create a genre. These are pulled from the tags in your files. Most are now using some form of Android as their OS and you can install other media player apps. I have several myself, and the same concept applies for all of them. They all use library management. If you make a change to any file after their libraries are built, they will need to be refreshed. Some do this better than others. Like I said earlier, in the worst cases you may need to delete that library and start from scratch. There isn’t anything mp3tag can do to remedy this.