How to properly export animation from .ba?

[Agility]

Yesterday I started writing binary animset (.ba) exporting tool and I'm currently stuck at nearly end as everything seems to be done correctly but ..it's shaking?

from original FBX format to AA
2

from BA to AA
2

As you can see animation exported from .ba is shaking (especially at the beginning), if there is anyone with knowledge I'd be glad for any idea how can I correct that

I will share it all when I'll fix this issue