webgl_loader_gltf sample with three.js r98 and r99.
As a result of comparison, r99 seems to be slightly brighter than r98.
I think that it is necessary to specify
THREE.sRGBEncoding in the environment map if it is over r99.
THREE.sRGBEncoding to the environment map will make the model darker, so I think further actions are necessary. Unfortunately I do not know how to do it.