sounds like a leaking capacitor/s on the power supply.
I had a small form pc a while ago, if I left it plugged in it was fine, the soft on/off button on the front would switch it on.
If I’d left it unplugged for any length of time then it would not switch on immediately, it would start up ~ 20-40 minutes later.
I lived with it for a while, but replaced the capacitors eventually as I didn’t want to leave it on all the time.
On a Foxsat, I’d be inclined to leave it plugged in all the time and let it go into standby. Ideally it needs to be plugged in and left on or in standby anyway for what people here call housekeeping which isn’t tidying up and hoovering when you’re not looking, but updating the EPG, checking for updates, updating the recording schedule etc. etc. I always leave my Humax boxes left on unless I have a good reason to physically power them down.