Network search fault

Hello,
Help me to find a solution for the problem with the network location and registration.
The situation is that we run test segment here with 1 BTS and standalone BSC, TSCM, MCS and HLR.The segment is on air but I can’t see this network in network list. I can see and register on this network only if I manually select ARFCN of BTS, after that I have a normal registration process and location update and can make calls to MSC phone or other phones that registered in segment by the same way. In case of I register in segment if I run manual network selection I can see only segment network but not other. It looks like that segment network and all other network somehow unsynchronized, so I can not see my segment if I am registered in other network and vise versa.
I try to analyze system information in TEMS during the network search process and clearly see that MS read all ARFCNs (my segment and surrounding networks) and can even detect BSIC. So I’am totally confused why I can not see my network segment during normal network search process.
Any help will be appreciated.