Have you paired the unit with the freesat app. If so it will wake every 20 mins to check with the server. The app will act as a good remote, with no wakeups, if unpaired.
When I first had my Freeview Humax box (5000T) I was seeing the same effect. I soon associated it with the use of the remote for another TV box (Topfield TF5800) which, on pressing its buttons, often resulted in the Humax box starting up.
Since the Topfield box died about a year ago the 5000T has never started up unexpectedly.
Maybe your Humax box is reacting to a different remote in a similar way.
When I first had my Freeview Humax box (5000T) I was seeing the same effect. I soon associated it with the use of the remote for another TV box (Topfield TF5800) which, on pressing its buttons, often resulted in the Humax box starting up.
Since the Topfield box died about a year ago the 5000T has never started up unexpectedly.
Maybe your Humax box is reacting to a different remote in a similar way.
I don’t think so as it happens when I have been using different devices each time.