Physics hit reaction different on different Meshes?!

I hope someone can help me to find out what is going on. I tried to rebuild unreals simple hit reaction (from the content examples) for my game. The problem i got is, when i do not apply an impulse to my character, but simulating the physics, it still gets an impact (from somewhere, and i can not find out why this is happening.) In the following picture u can see, that his head and upper body is getting an impact (i do not apply anything)


If i now change the Mesh (only the skeletal mesh in my mesh component, no settings or anything else) to the ue4 mannequin, it is not getting an impact. I already took the physics asset of the Ue4_Mannequin and linked it to my character mesh. Nothing changed, still an impact somewehre.

I hope anyone of you have an idea, why this is happening only to my mesh? If i activate my impact code, and replacing the sekeltal mesh to the ue4 ones, it is working perfectly fine, i get a similar result to the ContentExample (PhysicsAnimation). With my mesh this looks pretty bad because it get’s this impact on activate simulating anyways, and then my manual impact that i add need’s to “fight against the impact that is allready there” which makes it not looking nice. Is Physics simulation depending on the skeleton in anyway? Because this is the only thing i can think of right now.

I do not add any settings for u here because like i said, the mesh change fixes it. So it has to do with the mesh.