Device only reading a voltage on tester when touched.
So you meant IEC class II (i.e. double insulated), not class 2 (no, they aren't the same thing).

In this case there must be a fault somewhere, since in double insulated appliances any exposed metal parts should be floating. Citing Wikipedia:


  The basic requirement is that no single failure can result in dangerous voltage becoming exposed so that it might cause an electric shock and that this is achieved without relying on an earthed metal casing.


Unless the metal plate is energized from some unwanted external connection, the machines have some internal fault. Since both machines give the shock, I suspect they aren't properly designed as class II devices (it is unlikely that both machines failed in the same way, unless they are old and the fault developed in different time periods).

A professional electrician should inspect the connections to mains and a qualified technician should troubleshoot the machines: mains can kill, and such a symptom could foreshadow much worse outcomes, depending on how the internal construction of the machines is and the nature of the fault.