You could try the solution mentioned in this post.
In the FBX export settings, try swapping the primary and secondary bone axes (Primary/Secondary Bone Axis), as this can influence how rotations are interpreted when the animation is imported.
Also, when exporting the animation, try disabling the “Simplify” option or reducing its value (for example, to 0.1). This option optimizes keyframes and, in some cases, may introduce small variations that appear as jitter.
