This would be commonly happening when your socket connection was disconnected. Some exchnages like bittrex are explicitly showing the status of socket connections but I am not finding any option for poloniex to check the status of socket connections. Just changing browser or clearing cache may help.
Thanks for your reply. I usually use Firefox, also tried clearing the Cache/History/Cookies/Form data but didn't change anything. As you said I tried using Chrome, but still it is showing me this discrepancy and now it is happening for other coins too. This looks like the websocket/port issue. I wonder if I am the only one facing this or there are other having the same issue.
Thanks again.