Full information can be found on theAndroid Open Source Project - Issue Tracker:
https://code.google.com/p/android/issues/detail?id=11236 "DHCP client ignores lease time".
One thing that may help is to make sure the Cube(s) and any proxy are on addresses outside the DHCP pool so there will not be any collisions.
Thanks for the update on this.
It didn't affect me specifically because by default I did set the Cubes' IP addresses outside the DHCP (just an old habit), but I'm sure this will help others.