Bind to String Array Element, Bad_OutOfRange Quality

Ignition
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1

I have a string array tag and I'm binding to the individual elements.

If I drag the [0] element onto a property it gives me the tag binding path, then I change it to be indirect

[elevator]Test/Downstream_Eq_Numbers[0]
...
{1}/Downstream_Eq_Numbers[{2}]
#{1} = path
#{2} = index

This works fine when the index is 0. However, if I change the index to 1 I get a Bad_OutOfRange error on the binding, even though [elevator]Test/Downstream_Eq_Numbers[1] exists.

What am I doing wrong?

This string array element is bidirectionally bound to a dropdown