Question Blender BetterFBX export issue - Giving rotation issues in transitions

Hi everyone,
I am working on a personal project and I am currently facing an issue where when animation 1 transitions to animation 2 the character rotates randomly.

I am using the UMA pipeline for my game. For which I need a certain rig setup to be made.
Export Process -

1. I export the animation from the auto rig exporter (Universal type) to animation.fbx
2. Import the animation.fbx back to the blender and add three bones in the bone hierarchy then export using BetterFBX plugin in blender.
   
3. I do this for all the animations to make them compatible for UMA
   
4. When I put the animations in the controller and the animation I want it just randomly does some kind of rotation on the whole body. It doesn't happen for all the animations.

Gif of Transition error: https://media.giphy.com/media/jQhdPY8tPgoxdIxN6o/giphy.gif

I almost sure this is related to the BetterFBX plugin because I tested the animations for the same animations which have the issue on the Autorig exports and it did not rotate randomly.

I need BetterFBX export because it allows me to export the bone structure I want properly but if it is causing this issue I might explore other options.

I wanted to know if anybody has faced this issue or might know the cause of it?
Or maybe if I missing so settings that are causing this although every the export is exactly using the same setting for BetterFBX.