Rigged body doesn't appear correctly?

Hi

I’ve loaded skinned rigged mesh (separated gltf format from Blender 2.80) to threejs (r113). And it seems that rigged part of body stays always in default position during animation or stop frames and only not rigged parts are animated… what issue is this? Is this threejs issue or model issue? Previously I’ve tested animation without rigging and it works ok, now I’ve decided to use rigs for convenience and have got this problem…

Can you please share the glTF asset in this topic?

This could be an authoring issue in Blender so it would be useful if you explain how you have created the animation.

I’ve created simple model just for testing the rig… in blender you can see animation… but this animation doesn’t work in both https://sandbox.babylonjs.com/ and https://gltf-viewer.donmccurdy.com/
It uses Inverse Kinematics bone constraint. I’ve also used copy rotation constraint but i didn’t include it in this test for simplification.

test.gltf (31.3 KB)
test.blend (661.3 KB)

UPD
And here is the modified blender and gltf. I’ve added single bone animation to previous rigged animation and as you can see only this bone is animated… this is an issue I’ve described in the topic.
test.blend (662.3 KB)
test2.gltf (31.9 KB)

UPD2
Ok…I’ve made some research))… it seems that THREEJS doesn’t support IK in GLTF… so the question is there any posibility implement IK using GLTF? Or the only solution is using forward kinematics only, or some libs (but in this case I believe animation clips won’t be work and all animation should be made manually in code) ?