negative dot product

Hello,

I am running a simulation where I have a rigid body (shell elements) pushing into a deformable part.  Unfortunately, the simulation aborts with the following error:

The dot product -0.19758 cannot be negative for element 30050 instance xzy with record ID 844 at step 2 inc 1 kitgen 5.

This element (C3D4H) belongs to the deformable part and is within the body, so no not close to the contact at all.  At the point where the simulation aborts, this element is not deformed and the stress is basically 0 (E-6).