VLR problem

Hello folks, I have a strange behavior when the a MS send a Location Update, it is often rejected. I think the the problem is the "Rx GSUP LU Result without LU in progress" (see log further). It's weird because in the point of view of the HLR it seems OK : - message 0x04 Update Location Request followed by 0x10 Insert Subscriber Data Request - message 0x12 Insert Subscriber Data Result followed by 0x06 Update Location Result Is anyone experiencing the same problem? I will investigate in the code to see if I found something with the state machines or timers, if I found more detail, I will post them. Have a nice day, Antony Here is a extract of the logs of osmo-msc : 20180423132534278 DBSSAP <0010> a_iface_bssap.c:268 Rx BSSMAP COMPLETE L3 INFO (conn_id=4) 20180423132534278 DVLR <000e> vlr.c:388 New subscr, TMSI: 0xb35bd0aa 20180423132534278 DMSC <0006> a_iface_bssap.c:351 User has been accepted by MSC. 20180423132534748 DVLR <000e> gsm_04_08.c:3729 SUBSCR(MSISDN:1) VLR: update for IMSI=206012225318490 (MSISDN=1, used=2) 20180423132534748 DVLR <000e> vlr.c:769 SUBSCR(MSISDN:1) Rx GSUP LU Result without LU in progress 20180423132539279 DMM <0002> subscr_conn.c:110 Subscr_Conn(LU:3009138858)[0x1387410]{SUBSCR_CONN_S_AUTH_CIPH}: Close event, cause: CONGESTION 20180423132539279 DMM <0002> gsm_04_08.c:217 Subscriber IMSI:206012225318490: LOCATION UPDATING REJECT 20180423132539279 DMM <0002> vlr_lu_fsm.c:728 Subscr_Conn(LU:3009138858)[0x1387410]{SUBSCR_CONN_S_RELEASING}: Event SUBSCR_CONN_E_CN_CLOSE not permitted 20180423132539279 DBSSAP <0010> a_iface.c:419 (subscr IMSI:206012225318490, conn_id 4) Tx BSSMAP CLEAR COMMAND to BSC 20180423132539281 DBSSAP <0010> a_iface_bssap.c:241 (subscr IMSI:206012225318490, conn_id 4) Rx BSSMAP CLEAR COMPLETE, releasing SCCP connection