I have a Peak that I bought in March, and it died a month ago (booted up fine, but no power PAS or throttle). After a long wait ( a month), the LBS got a new display because the Minus button on the control pad had swollen up and wouldn't press. (I think they replaced the display more than once, along with replacing the controller, so I don't know what actually caused my original problem, or if my original display had this swollen button.)
When I went to pick up the bike, I noticed that the replacement display only had one brake cutout cable, so they took a Peak display from a bike on the floor. It also had a swollen minus button. They took one from another bike that wasn't swollen and installed that. It worked briefly, but soon after the minus button had swollen up and wouldn't work -- I didn't see it happen or smell it burning because I wasn't expecting it to happen. There appears to be something in the circuitry that's burning out this button (not just on my Peak, since one of the new bikes on their floor was also bad).
So now my bike is back at the LBS...soon it will have been in the shop more than I've had it at home.
Has anyone else seen this? Any idea what might be causing the problem?