Session Swapping during login

[tatasteel]

dear all please help us. we are useing otrs 4.0.3. frequently session swap between two users.
e,g
when somebody started working with some id filling up some faq suddenly session swap and the faq is being saved with different id. this occurrence have happened multiple time. and we got the following error in otrs log
[Wed Jan 7 17:53:21 2015][Notice][Kernel::System::Auth::DB::Auth] User: osj1088 authentication ok (Method: sha256, REMOTE_ADDR: 144.0.181.18).
[Wed Jan 7 17:56:49 2015][Notice][Kernel::System::AuthSession::DB::CheckSessionID] SessionID: 'jJ9P6mcgnrjWdQWuMjAIesLj00In4sRo' is invalid!!!

I am using following configuration in Framework -> Core::Session

SessionModule -db
SessionName - OTRSAgentInterface
CustomerPanelSessionName -OTRSCustomerInterface
SessionCheckRemoteIP-No
SessionDeleteIfNotRemoteID -No
SessionMaxTime-57600
SessionMaxIdleTime-21600
SessionActiveTime-600
SessionDeleteIfTimeToOld-yes
SessionUseCookie-No
SessionUseCookieAfterBrowserClose-no
SessionCSRFProtection-Yes
AgentSessionLimit-1000
AgentSessionPerUserLimit-10
CustomerSessionLimit-100
CustomerSessionPerUserLimit-20
SessionDir-<OTRS_CONFIG_Home>/var/sessions
SessionTable-sessions

[Rooobaaat]

Set SessionCheckRemoteIP from No to Yes.