THREE.WebGLProgram Warning Message - vNormal shader not read

I am seeing a warning message from most of the examples:

THREE.WebGLProgram: gl.getProgramInfoLog() WARNING: Output of vertex shader 'vNormal' not read by fragment shader
WARNING: Output of vertex shader 'webgl_4008bac2cdf4496d' not read by fragment shader

This might be related to the tree-vrm-girl.vrm model, since sphere.vrm will not have this warning. While I am trying my other vrm models, they will all print similar warnings, although the number of warnings will be different.

Is this something that can be removed by modifying the mtoon shader files?

[0b5vr]

Thank you! This is really helpful.

[Wei-1]

Here is my spec:

macOS Catalina, ver 10.15.7
MacBook Pro (13-inch, 2017, Two Thunderbolt 3 ports)
Processor 2.3 GHz Dual-Core Intel Core i5
Memory 8 GB 2133 MHz LPDDR3
Startup Disk Macintosh HD
Graphics Intel Iris Plus Graphics 640 1536 MB

I can see the warning messages using both Chrome and Firefox. It is not a breaking message.

Sample screenshot: