I don't know what this means
This means that if you use an IP address that is either IPv4 or IPv6, /dns will detect that and use that mode to resolve it. If you specify a host name, /dns cannot tell the difference, it will use the setting of the status window which is definied by the global setting, unless you specify -46 force it to use one or the other. At least, that's what I remember about the implementation. If it's not doing that, let me know.
local mode: cannot access ipv4 at all.
I have not been able to reproduce this so far. Can you describe a step by step method that reproduces this for you, including your global IP setting, server address, command used, etc.?