Skinned Meshes are imported incorrectly (not glTF spec conformant)
It seems that in some cases, glTF files with skinned meshes import incorrectly in Stager, producing wrong results.
This file exhibits that problem: https://github.com/prefrontalcortex/glTF-Sample-Models/raw/carbon-frame-bike/2.0/CarbonFrameBike/glTF-Binary/CarbonFrameBike.glb
It looks like Stager is not respecting the glTF spec here, which states that the transform of skinned nodes is irrelevant - their bones are the only thing that affects how the resulting mesh looks.

Actual (in any other glTF viewer I tried):

