I have 2 WLC 2504 controllers one master (WLC1_Master) and one slave (WLC2_Slave). With 30 access points 1260.
The problem is with "WPA2 PSK AES" security mode, the terminal's can not connecte correctly on the infrastructure but not with all APs, the problem does not appear always. It's work well with some APs and not with another. It’s impossible to work normaly. It loose lot of ping’s.
Only WEP authentication works without problem, the AP disconnect devices based on improper EAPOL handshake process. Changing of KEY does not help
On the Cisco WLC, we update 7.0 version to 7.2 without issue.
We update again 7.2 version to 7.4 (Last one) without issue.
I have some log from the device and from the WLC if it can help.