After upgrading from 1.1.10 to 1.1.11 our VM Slaves (configured as "Take this note on-line when in demand and off-line when idle) will no longer shut down.

To be more precise the idle counter is correctly triggered and the slave is disconnected. But afterwards the VM is not shut down (no command is send to the vSphere Server) and the Build slave reconnects and becomes online again.

Reverting back to 1.1.10 solves the problem.