Yep, you added an ‘Add Row’ action on submit of the form. Forms already add rows inherently (that is what they are designed to do). Adding another action to add a row is just redundant to what a form is already designed to do. Just remove the Add Row action and it will add only one row. With your Add Row action On Submit, you are telling it to add a second row after the first row is added.
You’ll notice that your second duplicate row doesn’t have the mp3 link. That’s because your Add Row action doesn’t fill that column, but the original form does add it because you already specified which columns to fill when laid out your form.