But recently I noticed some users have more than two records in the location table. For example one of the users has three different records with nearly the same information. The records are as follows. Is this behavior normal? (I am using Kamailio 4XX).

*************************** 1. row ***************************
           id: 171296745
         ruid: uloc-2c69-59db6c73-7ca-132d92
     username: 999999999999
       domain: NULL
      contact: sip:999999999999@5.106.35.18:10362
     received: sip:5.106.35.18:10361
         path: NULL
      expires: 2017-11-14 08:45:50
            q: -1.00
       callid: XpCnmaAhRF
         cseq: 43
last_modified: 2017-11-14 08:44:50
        flags: 0
       cflags: 64
   user_agent: android_1.1.0_samsung_SM-E500H_7b271714c08b942aa821fc756cdd2e890a37069e/1.1.0 (belle-sip/1.4.2)
       socket: udp:192.168.103.21:5060
      methods: NULL
     instance: <urn:uuid:8369ef6e-202b-4844-8928-492a7678c269>
       reg_id: 0
    server_id: 11369
connection_id: -1
    keepalive: 1
    partition: 14
*************************** 2. row ***************************
           id: 171296746
         ruid: uloc-2c69-59db6c73-7f2-eb5d92
     username: 999999999999
       domain: NULL
      contact: sip:999999999999@5.106.35.18:10362
     received: sip:5.106.35.18:10361
         path: NULL
      expires: 2017-11-14 08:45:50
            q: -1.00
       callid: BzMKuyJN8C
         cseq: 50
last_modified: 2017-11-14 08:44:50
        flags: 0
       cflags: 64
   user_agent: android_1.1.0_samsung_SM-E500H_7b271714c08b942aa821fc756cdd2e890a37069e/1.1.0 (belle-sip/1.4.2)
       socket: udp:192.168.103.21:5060
      methods: NULL
     instance: <urn:uuid:8369ef6e-202b-4844-8928-492a7678c269>
       reg_id: 0
    server_id: 11369
connection_id: -1
    keepalive: 1
    partition: 23
*************************** 3. row ***************************
           id: 171296747
         ruid: uloc-2c69-59db6c73-80f-541d92
     username: 999999999999
       domain: NULL
      contact: sip:999999999999@5.106.35.18:10362
     received: sip:5.106.35.18:10361
         path: NULL
      expires: 2017-11-14 08:45:50
            q: -1.00
       callid: 3p9P4PgZSv
         cseq: 51
last_modified: 2017-11-14 08:44:50
        flags: 0
       cflags: 64
   user_agent: android_1.1.0_samsung_SM-E500H_7b271714c08b942aa821fc756cdd2e890a37069e/1.1.0 (belle-sip/1.4.2)
       socket: udp:192.168.103.21:5060
      methods: NULL
     instance: <urn:uuid:8369ef6e-202b-4844-8928-492a7678c269>
       reg_id: 0
    server_id: 11369
connection_id: -1
    keepalive: 1
    partition: 15