Client Monitor issue

Hi to everyone. I'm rookie on forum and fortigate device.

i have a fortigate-80C on v.5.0 with 8 connected FAP21B on v.5.0. Everything goes OK for the seven (7)  FortiAPs on Wifi Controller -> Managed Access Points -> Managed FortiAP and Monitor -> Client Monitor, except for one FortiAP. The problem is: when i'm clicking on Wifi Controller -> Managed Access Points -> Managed FortiAP -> Client and choose Radio 1:1 goes (correct) to Monitor and Client Monitor but...... on the right view pane i have no title-labels, no columns, no SSID, no clients, no total (pages) etc. Only just on top, a grey null bar. On the other FortiAPs i have all the elements: SSID, FortiAP, User, IP, Device, Auth. etc.   Is that means anything for you ??

Thanks for your time.