Lena X2 handover not working

[Bob]

I'm running the lena-X2-handover example, with multiple UEs (5) and eNBs (2), for about 10 seconds. 

I'm getting this error message, every time the network has been created:

....

'build' finished successfully (2.314s)

0.029 /NodeList/5/DeviceList/0/LteUeRrc/ConnectionEstablished UE IMSI 2: connected to CellId 1 with RNTI 3

0.029 /NodeList/6/DeviceList/0/LteUeRrc/ConnectionEstablished UE IMSI 3: connected to CellId 1 with RNTI 4

0.029 /NodeList/7/DeviceList/0/LteUeRrc/ConnectionEstablished UE IMSI 4: connected to CellId 1 with RNTI 2

0.029 /NodeList/8/DeviceList/0/LteUeRrc/ConnectionEstablished UE IMSI 5: connected to CellId 1 with RNTI 1

0.033 /NodeList/4/DeviceList/0/LteUeRrc/ConnectionEstablished UE IMSI 1: connected to CellId 1 with RNTI 6

0.0409286 /NodeList/2/DeviceList/0/LteEnbRrc/ConnectionEstablished eNB CellId 1: successful connection of UE with IMSI 2 RNTI 3

0.0409286 /NodeList/2/DeviceList/0/LteEnbRrc/ConnectionEstablished eNB CellId 1: successful connection of UE with IMSI 3 RNTI 4

0.0409286 /NodeList/2/DeviceList/0/LteEnbRrc/ConnectionEstablished eNB CellId 1: successful connection of UE with IMSI 4 RNTI 2

0.0439286 /NodeList/2/DeviceList/0/LteEnbRrc/ConnectionEstablished eNB CellId 1: successful connection of UE with IMSI 5 RNTI 1

0.0529286 /NodeList/2/DeviceList/0/LteEnbRrc/ConnectionEstablished eNB CellId 1: successful connection of UE with IMSI 1 RNTI 6

0.1 /NodeList/2/DeviceList/0/LteEnbRrc/HandoverStart eNB CellId 1: start handover of UE with IMSI 1 RNTI 6 to CellId 2

0.104 /NodeList/4/DeviceList/0/LteUeRrc/HandoverStart UE IMSI 1: previously connected to CellId 1 with RNTI 6, doing handover to CellId 2

0.107214 /NodeList/4/DeviceList/0/LteUeRrc/HandoverEndOk UE IMSI 1: successful handover to CellId 2 with RNTI 1

0.117929 /NodeList/3/DeviceList/0/LteEnbRrc/HandoverEndOk eNB CellId 2: completed handover of UE with IMSI 1 RNTI 1

assert failed. cond="m_rxonBuffer[ m_vrR.GetValue () ].m_byteSegments.size () == 1", msg="Too many segments. PDU Reassembly process didn't work", file=../src/lte/model/lte-rlc-am.cc, line=815

terminate called without an active exception

Command ['.../ns-3-allinone/ns-3-dev/build/scratch/acs_test'] terminated with signal SIGIOT. Run it under a debugger to get more information (./waf --run <program> --command-template="gdb --args %s <args>").

I'm not sure what the issue is.