C4D to Unreal Mesh getting random scaled/flickering

Hi, I’m new to Unreal and working on C4D to Unreal animation export/import process.

It seem to be importing the static model and some animation fine, but for certain animations,
mesh seems to be getting random squishy scaling/flickering.

Below is showing C4D screenshot

Below is showing Unreal Screenshot


As you can see… body and legs are fine,
but the swinging arms are getting weird disconnect, scaling/squish problem in Unreal Editor… what am I doing wrong here… please help!

thank you!