Unity Booth Avatar Problem

I only seem to have this problem with booth avatars, manually attach clothes and the boob physics break, avatar tools don't work with some assets meaning manual is the only way i know of.
I simply attach the armatures in the corresponding places and it always breaks ONLY in the chest, suggestions?

If it helps i'm trying to put on the "Extension hyper tech" for Kikyo but sadly all clothes which i can't use avatar tools for do the same exact thing.

This post is deleted!
This post is deleted!

this tool definitely solves the problem

https://booth.pm/ja/items/3639300

@sakura99 Lifesaver!