KVM on ESXi causes segmentation faults in guest VMs with more than one vCPU

This post is related to this one:

OpenStack (KVM/QEMU) in vSphere - Occasionally segfaults occurring in OpenStack VMs with more than one vCPU configured

I was able to narrow down the problem described above. I have setup a vSphere VM based on Ubuntu 16.04 and installed KVM. I defined several guest VMs based on different Linux operating systems. When you add more than one vCPU to one  KVM guest VM, you occasionally receive segmentation faults in different processes unforeseeable where and when. The probability increases when you add more vCPUs and when the hosting machine is under high load.

I know that nested virtualization is not officially support, but we are so close. The scenario can be reproduced easily.

Is someone out there, who can support me getting KVM properly running?

Regards,

Jens