Hi Andre,
1. Please share the firmware running on the IAP's.
2. When the client loses wireless connectivity,
a) Does the client gets disconnected from the wireless ?
b) Does the client shows as connected & but is unable to pass any traffic?
Is the issue seen intermittently or reproducible all the time ?
Please share the SSID config along with the following outputs collected at time of issue:
1. show ap debug mgmt-frames <mac-address of client>
2. show ap debug auth-trace-buf <mac-address of client>
3. show tech-support client <mac-address of client>