Unity normalizing tangents on import from .fbx file?

I'm trying to pass the results of a 6-coloring graph algorithm ran on a mesh into Unity via an fbx file. I'm using both the fbx's vertex colors and tangents to hold the results for me. After importing the mesh with both normals and tangets set to "Import," I ran a simple Unity script to print the imported mesh's tangent and color values. I saw that while the colors were the same as what I wrote to the original fbx file, the tangents were tampered with. For example, (0.1, 0.1, 0.1, 1) is being mapped to ~(0.6, 0.6, 0.6, 1).

In mesh's material's shader, I've set #pragma glsl_no_auto_normalization, and the tag "DisableBatching" = "True". None of this helped. Is there an import setting I'm missing?