Can't delete v6 addy from gif0

[Frank Steinborn]

Hello,

i'm trying to delete an IPv6-address from my gif-interface (named
blazing):

shodan:~# ifconfig blazing inet6 delete 2001:1638:17ad::9 
ifconfig: ioctl (SIOCDIFADDR): Can't assign requested address

I tried 2001:1638:17ad:0:0:0:0:9 too without success. Adding the
address (ifconfig blazing inet6 add) worked fine, though. Any hints?

Thanks, Frank