Devices are getting ipv6 when ipv6 is disabled on the lan section


Hello guys,
i have a problem with the GWN7000 router that i am using for my home network. I have 2 networks configured, the first one is my main home one ( and the second one is my guest network ( In both of then as you can probably see from the screenshots i have ipv6 disabled as i don’t want ipv6 in either of the networks. The problem that i am facing right now is that some of my devices are getting ipv6 addresses and when i turn them off they seem to stay online for the router in the clients tab. is there anything i can do to prevent that. For example my desktop-pc ( at the time of capturing the screenshots is not powered on and the router is saying that it is online.