[jitsi-users] Registrarless SIP communication problem after an extra contact is added on contacts list

I am having some problem while using Jitsi in registrarless mode. I have two registrarless SIP account on two computers (Windows 7 - x86) . They are communicating (instant messaging) each other very well. When i add and extra contact (which has a legal registrarless sip id but not connected to network) to the contacts list of one of them, things are getting problematic. The account which has this extra contact is having below problems.
1. The account and its contacts goes offline, waits 2-5 seconds at this state and then goes online again periodically. (The extra contact that we added later is always offline, because there is no account on network for it.) This behavior repeats itself for a while. I guess this period is equal to "keep alive interval" value for this account. I can send instant messages to each other while this things happen, except offline to online transitions.
2. After having this behavior for a while, contacts goes offline permanently and communication can not be established. If i restart the Jitsi, then everything starts again.
I am using Jitsi 2.8.5426.

Could you help me about this?
Thank you...