From blender tracker : https://developer.blender.org/T60147
Different result in 2.79 and 2.8
.blend and generated gltf files are provided in blender tracker
Confirmed. Here is the model:
This appears to be a good test case for upcoming skinning fixes, so I'm moving to MS VII. If it's not in scope feel free to reassign it.
Not sure when this was fixed, but with #412 it definitely is
@UX3D-becher the exported animated glTF file is now OK in other software but get broken when imported (left):

@capnm That sounds like a possible importer issue, can you create a new issue for that? Thanks!
No need to create a new issue, this is a duplicate of #419
This is a known TODO, tangents are not managed yet in CUBICSPLINE interpolation
See https://developer.blender.org/T63475 for a workaround
Most helpful comment
No need to create a new issue, this is a duplicate of #419
This is a known TODO, tangents are not managed yet in CUBICSPLINE interpolation
See https://developer.blender.org/T63475 for a workaround