Element I - USB always powered?

[Piotr]

In my Elements I both USB sockets are always 5V powered, even after turning the device off. 
Is it intentional, or is it a bug to be corrected in some new firmware update?

[Wei Cao]

Yes, the ARM core does not power off even if the unit is in Standby mode (the status you mentioned "device off", it actually is Standby)
So that the unit can be back to working status in a very short time when you want to use it.