So the only thing I see logged - Defconf offering lease xxx.xxx.xxx.x for AB:CD:EF:GI:MN without success. And no connection so far for device that is stuck with DHCP
And it happens ONLY with 5GHZ WIFI! - turning to 2.4GHz n connection leaves the DHCP problem behind - but it's not a solution because I need more bandwidth than 20mhz/n channel can provide.

What can it be? Why DHCP is so allergic to 5GHz?