jSonDocument property: sometimes null, sometimes not!

Created by: vaz83

Hi, i have the following code: `void read() { if (SPIFFS.begin()) { if(SPIFFS.exists("/dev.json")) { File infoFile = SPIFFS.open("/dev.json", "r"); if(infoFile) { size_t size = infoFile.size(); std::unique_ptr<char[]> buf(new char[size]); infoFile.readBytes(buf.get(), size);

    DynamicJsonDocument jDoc(1500);
    DeserializationError error = deserializeJson(jDoc,buf.get());
    if(!error)
    {
      if(jDoc["GUID"]!=NULL)
      {
          String tempstr = jDoc["GUID"];
          if(tempstr.startsWith("SECURED."))
          {
            tempstr.replace("SECURED.","");
            jDoc["GUID"] = tempstr;
            tempstr.toCharArray(GUID,80);
            XORcrypt(GUID);
          }
          else
            strcpy(GUID, jDoc["GUID"]);
      }
    }
  }
}

}`

What i am facing now is that the condition if(jDoc["GUID"]!=NULL) is returning false, and when i pass jDoc["GUID"] to a string variable it has value! the property exists and has data. Why is it returning null? in another part of the code when i open other json files this condition works just fine, please help