Some instruments are always shuffled as last in the list despite the part number

[Elaini]

Let's say I want these parts:

1 - Basic Flute 2 - Lonely Mountain Fiddle 3 - Basic Horn 4 - Basic Drum

Still it will shuffle the order of the parts so one of the instruments is always last like this:

1 - Basic Flute 3 - Basic Horn 4 - Basic Drum 2 - Lonely Mountain Fiddle

The instruments in question are both Lutes and all Fiddles. Everything else stays in the wanted order.