Imported bone transform is different from origin

Hello,
I have created a character and animation in Blender. First i exported the Mesh to UE4 then the animation. The Mesh and its skelleton is working fine and i can rotate it. But when i import the animation, the upper left arm doesnt animate.

EDIT: I found the solution. For whatever reason i had to roll the bone. I rolled it by 1 and it worked.

And here the animation

I hope someone can help me, im trying to fix this for hours

blender is sucks