This article covers the original Chatter kit, not Chatter 2.0.
A button that reads as permanently pressed is nearly always a solder bridge on that button's pins — a little solder spanning two pins that should be separate. It is one of the most common things to happen during a build, and it is a few minutes' work to put right.
What to check:
Take the casings off so you can see the underside of the board around the button that is misbehaving.
Look at that button's pins under good light. A bridge shows up as solder running between two neighbouring pins instead of sitting as a separate cone on each.
Reheat the joint and lift the excess away with a desoldering wick or pump, then check the pins are clearly separate again. There is a step-by-step version of this in I messed up a soldering joint and the solder is touching two pins. How do I fix it?
If the joints look clean, check the button is sitting flat against the board rather than at an angle, and that nothing in the casing is resting on it.
Run the hardware test again with the casings still off.
If it still reports the button as pressed, take sharp, well-lit photos of both sides of your circuit board and send them to us here, or by email to [email protected]. We will look at the joints for you and tell you what we can see.