I have created a analytics dashboard in sandbox which include dates and related data and migrated it to production, but in production data for last few months are not showing up, please help

Hi,
I integrated Snap-in chat in my website. It's working fine, after refreshing & navigate to another page. The session is persistant in these cases. But, whenever i open a new tab ( not different browser or private window ) the chat is creating new session. So, for same user i am getting mutiple chat.

I tried with live agnet also. It's not working with refresh also. In live agent, after refresh also new chat is creating. New session.

I checked the cookies, session stroages, local storage. But, i am not finding any differance in tabs. I come across X-LIVEAGENT-SESSION-KEY in request header. But i am not able to reset the value. 
Can any one tell me how i can retain my session across all tab?
Can we implement it in our side, with live agent REST api?

Please suggest.