It's very strange. As you said the preset is working. But in some cases, it doesn't work.
Try this. Enter this value to display artist tag:
AAA, violin; BBB, piano
And save tag editor. If you open multiple artist splitter dialog, it will show the two artists properly.
Now run the preset, then you will get syntax error.
If you edit any of those values in artist splitter and save it again, then it works.
I can't make sense of this.