Hotpoint Aquarius TVFS 83 – mystery beeps

This dryer has had the recall safety upgrade.
Occasionally, when not in use – door open, program selector at OFF; the machine makes the three rising beeps noise that it usually makes when you select a program with the rotary knob.
A couple of seconds later it makes the three falling beeps – the ones it usually makes when you turn the rotary knob to OFF.
Machine doesn’t actually start, presumably because the door’s open.

The dryer seems to work OK when needed, I’m just concerned that it might really be switching power on and off and could be a fire risk.
Yes I know I could unplug it from the mains when not in use, but that’s a real faff in this location.

Any ideas? I’ve heard that the controllers sometimes need resetting and that can be done by leaving unplugged for a few hours. Well it’s unplugged now, but even when I plug it in again it might be a while before I know whether it’s fixed; the phantom beeping only happens occasionally and at random.