华为WCDMA未接通问题

请问在做VP业务时的一个未接通问题，信令方面在通过Security Mode Complete后，NAS上报一个Register信令后NAS就直接下发一个Release Complete，请问这个是什么问题，在NAS OTA MESSAGE消息里显示的是

信令是这样的：RRC Connection Repuest
                            RRC Connection Setup
                            RRC Connection Setup Complete
                            CM Service Repuest
                            Initial Direct Transfer
                            Measurement Control
                            Downlink Direct Transfer
                            Authentication Repuest
                            Authentication Response
                            Uplink Direct Transfer
                            Security Mode Command
                            Security Mode Complete
                            Register
                            Uplink Direct Transfer
                            Downlink Direct Transfer
                            Release Complete
                            RRC Connection Release
                            RRC Connection Release Complete

主要是Register这条信令，正常信令里面是没有这条信令的。