Problems with skinned mesh bones animationts

Hey there, got a mesh deform model animation problem here.

Once our animator completed the animation, it wasn’t playing the way it should. As seen in the video I’ve sent, it seems like one of the bone is broken and not moving with the animation.

In Blender, this does not happen at all. He has opened the model in both Moon Animator and Roblox Animator. It appears that the bone itself is completely missing from Moon Animator for that specific part yet it does show on the Roblox Animator while missing a joint BUT on the imported new animation, it doesn’t move like it’s anchored? (Images and videos provided will make it easier to see). Previous animations made on this model also works without a problem but exporting this one specific animation has caused some kind of unknown problem that we don’t have a clear answer to fix.

Hopefully someone can help fix this. Thanks for reading.

https://cdn.discordapp.com/attachments/1090601272845008916/1300138227814105252/stupidfbx.mp4?ex=671fbf94&is=671e6e14&hm=83bfe07de09a4383d7b03a9d468595e6d84a865f600127009334a0d53c4e2f4e&

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