Exporting displayColor set results in nan values

**Describe the bug**
When exporting geometry containg a color set that has negative values, the resulting color value becomes nan.

**Steps to reproduce**
1. Create a piece of geometry (a cube in this case) with a USD preview shader. Set the values to a negative value. (ex: (1.2, -0.2, 4))
2. Export selected as USD. Make sure you are exporting color sets and displayColor
3. Here is the result:

```openUSD
#usda 1.0
(
defaultPrim = "pCube1"
metersPerUnit = 0.01
upAxis = "Y"
)

def Mesh "pCube1" (
prepend apiSchemas = ["MaterialBindingAPI"]
kind = "component"
)
{
uniform bool doubleSided = 1
float3[] extent = [(-0.5, -0.5, -0.5), (0.5, 0.5, 0.5)]
int[] faceVertexCounts = [4, 4, 4, 4, 4, 4]
int[] faceVertexIndices = [0, 1, 3, 2, 2, 3, 5, 4, 4, 5, 7, 6, 6, 7, 1, 0, 1, 7, 5, 3, 6, 0, 2, 4]
rel material:binding =
point3f[] points = [(-0.5, -0.5, 0.5), (0.5, -0.5, 0.5), (-0.5, 0.5, 0.5), (0.5, 0.5, 0.5), (-0.5, 0.5, -0.5), (0.5, 0.5, -0.5), (-0.5, -0.5, -0.5), (0.5, -0.5, -0.5)]
color3f[] primvars:displayColor = [(1.4934778, nan, 21.112127)] (
customData = {
dictionary Maya = {
bool generated = 1
}
}
)

def Scope "mtl"
{
def Material "usdPreviewSurface2SG"
{
token outputs:surface.connect =

def Shader "usdPreviewSurface2"
{
uniform token info:id = "UsdPreviewSurface"
color3f inputs:diffuseColor = (1.2, -0.2, 4)
token outputs:displacement
token outputs:surface
}
}
}
}
```

**Expected behavior**
I would have expected the value to be the result of the diffuseColor having the ASECcg transformation applied.

sRGB -> ASECcg:
sRGB value: (1.2, -0.2, 4)
Expected ASECcg value: (2.124096632003784, 0.43282783031463623, 22.048145294189453)

Why is the result (1.4934778, nan, 21.112127)? Where did the nan come from?

I'm by no means an expert at color transformations, so I may have fundamentally misunderstood something, but I'm happy to learn. Thanks!