It's likely the wiimote is at fault.
3rd party wiimotes many times don't entirely mimic the nintendo wiimote behavior. Enough to work with a wii, but not entirely. Sometimes those deviations in behavior is enough to break it for Dolphin.
3rd party wiimotes many times don't entirely mimic the nintendo wiimote behavior. Enough to work with a wii, but not entirely. Sometimes those deviations in behavior is enough to break it for Dolphin.