Partial Deformation in animation after importing to ue4

It’s been some time that this happened and I tried everything that I know and also searching the web, but I still can’t sole it.

It’s normal when it’s in blender but for some reason the animation at some point freaks out in ue4 and i don’t know the reason why it’s doing that.

It happened only for the lower leg. Also I’ve deleted the animation and then made a new one it’s the exact same problem that’s happening for me.

Maybe because I use IK in blender?

If you can help i will be thankfull :smiley: