This is a nice easy one - you have sticking buttons. It's not software.

The four buttons can stick quite easily, either because of crud between the buttons and the holes in the fascia, or because the fascia has at some point been screwed down too hard in the past.

The remedy is to remove the fascia using the correct size allen key. Carefully clean out the apertures in the fascia with a cotton wool swab and alcohol. Check that your buttons are also clean, and free of swarf. The original buttons were well manufactured with no flash or swarf. I have also taken to gently filing the inside of the bottom button aperture of the fascia with a triangular diamond jeweller's file to improve the fit of the button in the fascia. Do this slowly and carefully, trying the button in the aperture regularly. Don't go too far! (don't worry if you do - I have loads of fascias available).

When you replace the panel, make sure that you fit the top (round) button onto the switch with the correct orientation. It's possible to fit the button 90 degrees off so that it stands slightly proud and remains "pressed" when you replace the fascia.

Check that the lense sits correctly inside the fascia aperture as you put the fascia back on: then tighten the screws 'till "finger tight". You only need to tighten them about 1/6th of a turn further - DON'T be tempted to grind them in.

Test the physical operation of the buttons before you power on, and check that they all click distinctly when pressed, as well as when they are released. If they are "already pressed" or don't release properly, unscrew the two panel screws nearest the buttons by about a quarter turn and re-try.

If this doesn't sort it out, post again.