Ipv6 address stored differently while using Inet type

[Sameer Thakur]

Hello,
I am using Postgres 10.4
I tried to insert ipv6 address '2001:db8:3333:4444:5555:6666:1.2.3.4'
in Postgres (10.4) in an inet column. It is stored as
2001:db8:3333:4444:5555:6666:102:304.
Why is the IP stored differently?
Does the stored IP represent the same one being inserted?
 Is this a known bug resolved in later versions of Postgres?
Thank you
Sameer