Unexpected !! Radacct session

[Srijan]

Hello,

I got some query about the radacct session while implementing dual stack,
notice this extra row (which has been highlighted below) for each user on
both v2 as well as v3.  Is this natural/something wrong or ts outcome of
dual stack implementation. All the accounting update are done in first
session row & when user disconnected both session are closed.

+-----------+--------------------------+------------------+----------------+-----------+-------+-----------------+-----------+-------------+---------------------+--------------+-----------------+---------------+-------------------+------------------+-----------------+------------------+-----------------+------------------+--------------------+-------------+----------------+-----------------+----------------+---------------+----------------------+-------------------+----------------+-------------------------+-------------------------+
| radacctid | acctsessionid            | acctuniqueid     | username
| groupname | realm | nasipaddress    | nasportid | nasporttype |
acctstarttime       | acctstoptime | acctsessiontime | acctauthentic |
connectinfo_start | connectinfo_stop | acctinputoctets | acctoutputoctets |
calledstationid | callingstationid | acctterminatecause | servicetype |
framedprotocol | framedipaddress | acctstartdelay | acctstopdelay |
xascendsessionsvrkey | framedipv6address | framedipv6pool |
framedipv6prefix        | delegatedipv6prefix     |
+-----------+--------------------------+------------------+----------------+-----------+-------+-----------------+-----------+-------------+---------------------+--------------+-----------------+---------------+-------------------+------------------+-----------------+------------------+-----------------+------------------+--------------------+-------------+----------------+-----------------+----------------+---------------+----------------------+-------------------+----------------+-------------------------+-------------------------+
|    311744 | 476813                   | 5a7b5047897895fa | a09d.86c3.4ff5
|           |       | 192.168.1.100 | 4194424   | Ethernet    | 2019-06-03
22:01:52 | NULL         |           77387 | RADIUS        |
  |                  |       785151936 |       5720321446 |
|                  |                    | Framed-User |                |
100.91.7.187    |              9 |             0 |                      |
NULL              | v6-pool   | 2400:xxxx:8002::c36/128 |
2400:xxxx:8003:47a::/64 |
*|    311745 | 476813:476815-1559578603 | 96c1000a9095e826 | a09d.86c3.4ff5
|           |       | 192.168.1.100 | 4194424   | Ethernet    | 2019-06-03
22:01:52 | NULL         |               0 | RADIUS        |
  |                  |               0 |                0 |
|                  |                    | Framed-User |                |
100.91.7.187    |              9 |             0 |                      |
NULL              | v6-pool   | 2400:xxxx:8002::c36/128 |
2400:xxxx:8003:47a::/64 |*
+-----------+--------------------------+------------------+----------------+-----------+-------+-----------------+-----------+-------------+---------------------+--------------+-----------------+---------------+-------------------+------------------+-----------------+------------------+-----------------+------------------+--------------------+-------------+----------------+-----------------+----------------+---------------+----------------------+-------------------+----------------+-------------------------+-------------------------+
2 rows in set (0.00 sec)

Regards,