The "bed time" parental controls do not apply to IPv6, only to IPv4. This can be easily tested, on a device which has IPv6 enabled, by going to something like YouTube and watching a video before "bed time" starts, and then continuing to watch once "bed time" has happpened. If the device has access to IPv6 DNS as well, it can continue to browse YouTube and select other videos for example. Other IPv6 enabled sites work too of course, this is just an easy example.