Why do I get incorrect bounding boxes when I add a cloth component in Unity 2017.3?

Why do I get incorrect bounding boxes when I add a cloth component in Unity 2017.3?

I have a character with a cloth. The cloth is separated into its own mesh, but both the cloth and the character are in the same FBX import. The cloth is correctly skinned to the char so it moves with the animations.
However when I add a cloth component to the cloth, its skinned mesh renderer bounding box shows up very small in the scene view: (see it embedded in the character's waist here)

If I remove the root bone reference from the cloth, the skinned mesh renderer bounding box gets offset from the rendered position of the model:

As you can see something is very wrong here :D The problem is I don't know what, or how to fix it. I suspect that I might have to import the whole fbx in a different way but I'm just a programmer so I have no idea where to start.

Solutions/Answers:

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