@Jun_Wah_Soh, the problem you are running into has to do with the skeleton in the cloth mesh. I know that you mentioned that the skeletons of both meshes were identical, but when I open your Cloth_Geo_02.glb file in Blender, the skeleton that the mesh is bound to is missing legs, head, and portions of the arms:
Where the skeleton on the character is a complete skeleton:
If you want to just assign the skeleton from the cloth mesh to the character’s skeleton, you need to skin the cloth mesh to an exact copy of the character skeleton so that the skin has all the information it needs. It may seem unnecessary to have all of the bones of a character in a mesh of just a shirt, but The vertices need to have weight information for each bone in the hierarchy, and when you retarget a mesh to a skeleton with a different hierarchy, it can cause unexpected results like this.
I hope this helps, but please let me know if you have more questions.