Multiple Session for same user

Hi,

This issue is local however is troublesome

--User is using two session using same ID.
--One session User runs query on Service Request and other he is creating correspondence.

-- User is using extended Monitors ( 2 monitors)

Now Every day at least once the session where SR is being queried session's out.

I have attempted
--Clearing cache/cookies
--disabling Add-ons
--resolution check on the two monitors.
--Have tried using just one monitor as well.

Any suggestion or Advise is appreciated

Thanks
Atul