Might want to move this to the Troubleshooting section, where it'll get Mica's attention quicker.
My gut says exercise the snot out of it. If that doesn't fix it, then yeah, probably circuit board.
*on second thought (been a minute since I had a Distillate...) that's a cut/flat/boost switch. So it cuts, and it works as flat, but no boost? That sounds like a switch glitch. Flick that thing about 95 times.