Imported FBX Aniamtion Skin(?) Issue

Hey guys and girls,

i’ve encountered some strange issue while setingup a full character animation set.
There’s one animation (in my case the Jump-Anim, and it seems only this one) that has to struggle with some broken skinning(?) on both Arms.
Have a look please:


But in Maya it works all very well. As you can see here:


Also, when importing the skeletal mesh I get the message:

FBX bind pose ‘skincluster2’ is invalid. It will be ignored.