Scenario is handover on S1AP, data forwarding is enabled, and
the Source ENB is forwarding DL PDCP packets to EPC(SGWU)
with PDCP SN included. SGWU is also forwarding these packets
to the Target ENB.
However the PDCP SN is not present in the forwarded packets
from SGWU to Target ENB.
I modified this part, and there was the same problem in 5GC, fixed it as well.
A lot of code in GTP-U has been modified,
so if you have any problems, please let us know right away.