Hello,

Use 802.11n with WPA2-PSK authentication (AES), even with great signal, some customers disconnect and connect frequently and the log shows "Connected, wants bridge." What could be happening?

Alexandre

I believe that means that the device that is connecting is telling the access point that it is a bridge, and will be passing data for other devices. 
In other words, it will have multiple MAC addresses that it will be passing data for.

Ok, but I think the problem is when you disconnect, the following message appears in the log "Disconnected, management-protection failure". Now, for example, all customers disconnected and log "Disconnected, request to disconnected from registration table".

turn off Management Protection, unless you are using it - in which case, set a password.