We don’t know exactly the problem, but according to the trace we found a HANDOVER Failure between the MSC-BSC, i.e. the MME request from HO to MSC and the MSC returns an HO failure to the BSC.
I recommend to contrast the information of LAC, Cellid in BSC and MSC. Maybe check network LAC between MSC’s just in case. According to standard, value 7 is for interworking. Some parameter is not set correctly/matching either on 2G side or 4G side. Double check and maybe the answer is there.