How last setting be memorized on Moon P5.3?

After a listening session are you turning the unit off in the rear or from the front via the "Standby" button? If from the rear this may very well be normal. If by the Standby on the front you may have a problem. Simaudio units are designed to be left on via the rear switch and and turned on and off for listening sessions via the Standby in front.

Valinar, thanks.
after reading yr advice, I did try something and you were right.
I normally turn it off at the front using a remote and left stdby s/w at the back at "on" BUT I am using a step down xformer so I unplugged this unit every time I finished. That's why!