What happened if I plant two C CML into one Ubuntu machine?

[kevingzhang]

There would be conflict so none of them will work.
but you can still see they are active mining in the UI but that was not true. They are showing active but the AA algorithm cannot run. Therefore you won't have any reward. You are wasting your resources and CMLs lives.
You can use multipass to create multiple VMs and plant C CML separately. That will works as long as it is a C CML. There is another discussion topic on Multipass.