Airport DHCP issue

I have searched for this issue and have not been found another thread addressing this. I apologize if I missed it. Here is my problem. I have seen this in 3 environments with different variables. Any help would be appreciated, Join airport network. Icon in menu bar shows I am on the NW. But no IP address is assigned. If I open Airport Utility I see the airport and within seconds I get an IP address. If this does not work then I have to restart, either the client or the airport and then an IP address is assigned. I have tried turning airport connection on and off on the client, no luck. I have had reports, and experienced this issue in 3 separate networks. Each slightly different. In some the airport extreme was the DHCP server acting as a router. In others it was in bridge mode passing DHCP through from OS X server. In some the AE is running 7.1 or 7.1.1 or 7.2.1. In some the express was connected over ethernet extending the network in others it is extending the network via WDS. If the express is connected via ethernet it maintains an IP, if it is connected via WDS it may lose it's IP. Only wireless clients are affected. Wired clients work fine. Only commonality in all situations is the presence of both a airport extreme and an airport express. I have rebuilt 2 of the 3 networks I have seen this on from the ground up after resetting all base stations to factory defaults. The issue resurfaces within days. Anyone else experiencing this? Any ideas on how to fix it? Thanks in advance for just reading this thread.