While I have not conclusively proved this, I believe this is an issue related to how OSX handles HID devices with multiple Report IDs.
As a workaround, you can use the adapter in WiiU mode with my drivers installed: https://github.com/area/osx-wiiu-gcc-adapter/releases
As a workaround, you can use the adapter in WiiU mode with my drivers installed: https://github.com/area/osx-wiiu-gcc-adapter/releases
