multiple tentative ipv6 address are applied to a network interface

Issue

• multiple tentative ipv6 addresses are applied to a network interface.
• The number of IPv6 addresses has changed between before and after migrating this instance.

Before migration

4: ens224    inet6 fe80::aaaa:aaaa:aaaa:aaaa/64 scope link dadfailed tentative noprefixroute \       valid_lft forever preferred_lft forever
4: ens224    inet6 fe80::bbbb:bbbb:bbbb:bbbb/64 scope link dadfailed tentative noprefixroute \       valid_lft forever preferred_lft forever
4: ens224    inet6 fe80::cccc:cccc:cccc:cccc/64 scope link dadfailed tentative noprefixroute \       valid_lft forever preferred_lft forever

After migration

4: ens224    inet6 fe80::aaaa:aaaa:aaaa:aaaa/64 scope link dadfailed tentative noprefixroute \       valid_lft forever preferred_lft forever
4: ens224    inet6 fe80::bbbb:bbbb:bbbb:bbbb/64 scope link noprefixroute \       valid_lft forever preferred_lft forever

• These messages can be seen.

Sep  2 09:13:10 HOSTNAME kernel: IPv6: ens224: IPv6 duplicate address bbbb:bbbb:bbbb:bbbb used by xx:xx:xx:xx:xx:xx detected!
Sep  2 09:13:10 HOSTNAME NetworkManager[1068]: <info>  [1630541590.2105] device (ens224): ipv6: duplicate address check failed for the bbbb:bbbb:bbbb:bbbb/64 lft forever pref forever lifetime 3-0[4294967295,4294967295] dev 4 flags permanent,noprefixroute,tentative,0x8 src kernel address
...
Sep  2 09:13:10 HOSTNAME NetworkManager[1068]: <info>  [1630541590.9106] device (ens224): ipv6: duplicate address check failed for the bbbb:bbbb:bbbb:bbbb/64 lft forever pref forever lifetime 4-0[4294967295,4294967295] dev 4 flags permanent,noprefixroute,tentative,0x8 src kernel address
Sep  2 09:13:10 HOSTNAME NetworkManager[1068]: <warn>  [1630541590.9106] device (ens224): linklocal6: failed to generate an address: Too many DAD collisions