JSON response not showing in JSON view

I got a strange issue. When calling a service that is returning JSON, it is not showing in the XML or JSON view.

From XML tab: <xml/>

From JSON tab: <Not JSON content>

From Raw tab:

HTTP/1.1 200 OK
Set-Cookie: JSESSIONID=c1eab944c1eabf400b1c938627d9
X-Backside-Transport: OK OK
Date: Tue, 18 Nov 2014 10:38:17 GMT
Content-Type: application/json; charset=utf8
Cache-Control: no-cache, no-store
X-Cache: MISS from cache-a1
Transfer-Encoding: chunked
Via: 1.1 cache-a1 (squid)
Connection: keep-alive

{
 "getAccountDetailsOut" : {
  "ibanNo" : "SE76 9500 0099 6042 0017 3237",
  "accountName" : "SALOMON MAURITZ",
  "topAccount" : 173237,
  "bankAccountNumber" : "173237",
  "BIC" : NDEASESS,
  "creditInterest" : 0.0,
  "creditLimit" : "",
  "dueDate" : "",
  "dueDateInterest" : "",
  "accountRoles" : [],
  "interestRates" : [{
    "interestRateExpaireDate" : "",
    "interestRate" : 0.0,
    "accuredInterest" : ,
    "amountBracket" : 0,
    00 till 50.000,
    00,
    "interestPaidDuringPrevoiusYear" :
   }, {
    "interestRateExpaireDate" : "",
    "interestRate" : 0.0,
    "accuredInterest" : ,
    "amountBracket" : 50.000,
    01 till 200.000,
    00,
    "interestPaidDuringPrevoiusYear" :
   }, {
    "interestRateExpaireDate" : "",
    "interestRate" : 0.25,
    "accuredInterest" : ,
    "amountBracket" : 200.000,
    01 och uppåt,
    "interestPaidDuringPrevoiusYear" :
   }
  ]
 }
}

PS. I have removed some customer data and added XXXX(test data, but still) and formated it using notepad++, but not changed the actuall JSON at all.

The JSON is valid. content-Type is also application/json.

There are no messages in any logs at all.

Any suggestions to what this might be? Other services on the same URL is working as expected. I could not find any similar issues, so I'm sorry if there are some, that didn't match my search criteria.