The first step is to ensure that you have the latest firmware installed so that all of the security updates have been applied. The next step would be to verify/configure client isolation on each SSID.
For A5/C5: http://ap.help.mimosa.co/ap-ug-wireless-ssid
Client isolation is on by default with both WiFi Interop and SRS protocols. In WiFi Interop, client isolation may be turned off for a given SSID on the A5 SSID page, but this is not recommended for most use cases. In SRS mode, client isolation cannot be turned off, but the ability to disable it is on our firmware roadmap.
For G2: http://wifi.help.mimosa.co/gw-ug-wireless-lan-ssids
Client isolation is also configured at the SSID level.