IPV6 test case
If we set a static ipv6 and IPV6_AUTOCONF was set to yes. the IPV6_AUTOCONF value will not take affect until we bring down the interface and bring it back up. Performing a network restar will not change the value of IPV6_AUTOCONF.. We have found that after a restart of the network service. The interface receives a second global 2001 address.
steps to duplicate
1. Add IPV6ADDR=
2. IPV6_AUTOCONF=yes change to no
3. restart the network manager or service
4. if you want to set the default gW use IPV6_DEFAULTGW=
Possible fix is to restart the interface or the below.
Set net.ipv6.conf.eth0.accept_ra to on in the sysctl file and set autoconf to off.
net.ipv6.conf.eth0.autoconf = 0
net.ipv6.conf.eth0.accept_ra = 1 << enable router advertisments
/sbin/sysctl -a | grep net.ipv6.conf.