issues about csfb

Hello. I have tested CSFB on several phones in different situations. Calls from 4G to 2G are always established, but calls from 2G to 4G and from 4G to 4G are not always successful (sometimes they connect, and sometimes they do not). For this test, the phone's location relative to my USRP antennas is fixed. It is noteworthy that I have set the 4G neighbor in Osmo-BSC, as well as the 2G ARFCN information in SIB7. I attched log file and pcap of osmo system. osmo system ip:192.168.75.192 srsran_4G ip:192.168.75.185 open5gs ip:192.168.75.181 I would be very grateful if anyone with experience in this field could help me.