> Sorry but I don't use cocoon, i always use cordova+crosswalk
>
you wrap your game with intel xdk ? i use intel too but the apk exported is too big
xdk is deprecated, i use Cordova CLI to build android apk.
anyway, try also changing resolution in 16:9, i think this white band problem could be the NON 16:9 resolution fit-screen, just change all at 960x540, then export and rebuild apk for a quick test