var respJson = '{"data":"\u2028"}' // this is kind of what client receives
var evalJson = 'var d='+respJson   // this is what SC transforms...
eval(evalJson)                     // ..to finally evaluate in this way

Uncaught SyntaxError: Invalid or unexpected token
    at <anonymous>:1:6
    at JSON.parse (<anonymous>)
    at Le (cb=gapi.loaded_0:73)
    at b (cb=gapi.loaded_0:226)

JSON.parse(respJson)              // this is valid though

eval(evalJson.replace(/\u2028/g,'\\u2028'))  // escaping it also would make it work