Threejs throws shader error when rendering certain cc4 models with merged mouth option enabled

Hi,
I am experiencing an error where when i load a model from cc4 (which was exported using “Mouth open as morph” option enabled) it throws error at rendering phase and uses 100% cpu. When i run it on bigger machine it starts to stutter with 1 frame per second.
This issue doesn’t happen if i using default export option in cc4. the reason i had to enable that option is to ensure i can move the mouth bone along with blendshape.
For my project once i export the model from cc4, i convert them to vrm in blender and load it in threejs using vrm loader.
So far only that specific export option is causing issue. Thats why i am wondering if its related to threejs, cc4 or both. My threejs revision is 144.