OK forget the Hive it is doing what it should be doing, the boiler should have a permanent live, so you have a display all the time, the hive only tells the boiler when to fire up, it does not power the boiler, you need to find why you have intermittent permanent live, where is the electrical switch for the boiler ? Turn the power off to the heating system, remove the hive receiver cover and post a pic of the wiring on the back plate