Bone Scale and Animation Retargeting

When working with Animation or control rigs(modular rigs as well) the engine in general doesn't play well with scaled bones.

To overcome this users should bake with Remove Scaling enabled

The above options works only for bones above root in the skeleton hierarchy. For root bone(or any other bone) scaling can be removed manually. After scaling, disable Update Children option in Bone Options side panel and set back the scale to 1.(don't forget to re-enable Update Children after you've completed this step).

Here's a video going through the process.