VMB1DM is going to 100% when disconnecting Velbus power

Dear,

When a VMB1DM is on (so its dimming value is different from 0%), and when I remove the 12V Velbus power supply (eg. Because the fuse of the velbus power supply transformer switches off), the VMB1DM goes into full on (dimming value 100%).
The only way then to switch off the lamp is to remove the 230V power supply of the light circuit or to switch on the 12V power supply of the Velbus.
Is this the normal working of the VMB1DM an is there a workaround to switch off the lamp when the 12V power supply of the Velbus is removed?

Thank you