LabVIEW Unit Test Framework: Test Vectors cause VI output to always be 0?

Hello, I'm trying out the Unit Test Framework. I'm struggling to make Test Vectors work correctly.

My unit test simply involves 1 VI that takes 2 numeric inputs and outputs their average.

When I manually set up every single test case and don't use Test Vectors, I get the expected results:

Manually entering every test case: The VI's outputs correctly reflect the inputs

However, when I apply the same inputs using Test Vectors, my VI always outputs 0 no matter what the inputs are:

Using test vectors: The VI's outputs are always 0

What's going on? (Test files attached -- LabVIEW 2020)