I have ipads that are running various iOS version, from 6.x to 7.x. They are authenticating with WPA2-PSK and mac authentication. They are authenticating just fine, but not leasing an IP address. When I turn off mac authentication, they get their IP address just fine. They are connecting to an SSID that is locally switching, the APs are in Flex connect mode running WLC code version 22.214.171.124
The dhcp source is a MS server running 2008R2. Other clients seem to be getting on just fine, it seems it is only with the ipads. I have attached a client debug of one of the ipads having the issue.