Hammer.min.js.map : Failed to load resource: the server responded with a status of 404 (Not Found) on iOS only

when I am running “ionic cordova run ios --prod”, m getting following error:

and as I told you in my this ( By mistake updated from ionic 3 to ionic 4 and now unable to go back to the ionic 3 ) post, m running the run command by adding this ‘-- --buildFlag="-UseModernBuildSystem=0"’, the error after adding this command
‘ionic cordova run ios – --buildFlag="-UseModernBuildSystem=0" --prod’ is following:

plz help me, m stuck here since many days @lucasbasquerotto