Noice from speakers when Naim turned off

Recently I noticed that there is a noise from the speakers when my Naim Nova is turned by HDMI (ARC) meaning when TV is shut off the Nova is auto shut off but leaving this idle noise in the speakers. When turning off by using the on/off on the front this noise stops.

Anybody noticed this?

what sort of noise? - if its hiss then that perfectly normal for naim when in standby.