Agilent E3648A odd behavior (+Video)

[The E Engineer]

Dear all,

This is my first post but i have been here as a guest for many years. Today I need your help.

I got an Agilent E3648A, used from ebay. The first channel does not go all the way to 0.00V. The minimum I can set is 0.3x volt and this voltage remains even when the output if OFF!
When I set the voltage to 8V for example, and disable the output, the power goes down to 0.3V not as instantly as the 2nd channel goes.

Any idea where to begin with?

Thank you in advance

-Update1: The behavior is like the output capacitor remains charged even when the power supply is disconnected from the mains. So the 0.3v stays and gradually goes down.

-Update2: See it in action: