I used the new gltf 2.0 exporter available in blender 2.8 to export a model with three separate elements two of which has gloss, reflection, and normal maps attached to it via principle bsdf one model has gloss value. The problem arises after exporting. The model with custom gloss value works fine but the ones having gloss and normal value through maps appears to have no gloss or normal value. Also I have combined the several separate models into one. I exported the models using. glb extension.