error about ACCESSOR_VECTOR3_NON_UNIT

I have a gltf error report:

ACCESSOR_VECTOR3_NON_UNIT 
Vector3 at accessor indices 519..521 is not of unit length: 1.6477635560178159. 
/meshes/0/primitives/0/attributes/NORMAL

And the value of Vector3 519…521 is -0.0571990832686424,0.996026694774628,0.0682575702667236.

I don’t see a question, but I think you also posted this on GitHub, so I think you are asking what this means.

Every vector3 for the normal mesh attribute are expected to be normalized (i.e. unit length, i.e. the length of the vector is 1).

The meshes section of the specification says this:

The error in the report is saying that this vector is not length of 1.