Animation is fine in 3D Software, but one body part starts shaking in Unity,Animation fine in 3D software, but a body part is shaking in Unity

Here’s a video of the issue. Animation is fine in Blender, but shaky in Unity. I also tried reimporting the fbx file into Blender and it’s fine animationwise. I am using Unity 2018.3.12f1.,Title says it. I have an animation from Blender and when I export it to fbx and into unity, one of the hands start shaking like crazy while also twisting the rig a little making the elbow look strange. There’s a video of the issue down below. I also tried importing the fbx file back into Blender and animationwise, everything is fine! I am using 2018.3.12f1 as my version.

Ok, apparently, I fixed it by importing the same fbx file, but fresh, under a new name. This new file is working, for some reason.