Hello, here is the model:
model_with_animation.gltf.zip (97.0 KB)
When I open the model in sandbox it is ok. The animation is playing and everything is as it should be.
But, the moment I click: Export to GLB the model breaks. It appears that everything with bones gets kind of flipped, but I cannot be sure, because I have not gotten into details.
It (almost) looks like the scene hand is flipped. Any idea @Drigax ?
Sounds plausible for round tripped glbs. I took a glance at the export code, however we don’t do any destructive actions on the scene during export. I’ll have to take a closer look to see if there’s anything else that we’re doing that may cause this as a side effect, and if the joint transforms are being modified.
Anything here?
cc @bghgary to double check but a lot of improvments have been done since then regarding export.
@hidroo Did you try it? 
The OP’s model works for me.
