We've been having a strange issue for months. Some Mac clients on the Wi-Fi lose connectivity to the gateway intermittently for a few seconds to minutes. We noticed this when users began complaining that they were "disconnecting" from Wi-Fi, but after setting up multiple pings, it's clear that they are losing connection to the local gateway as pings to other machines on the Wi-Fi network are fine. This mostly involves R710s with a virtual smart zone, and various Macbook clients.
I managed to capture traffic with Wireshark during one of these outages, and the pings go out from the client but are not answered by the gateway (SonicWALL in this case). I find it hard to believe this is a problem with the gateway as there are never problems with LAN clients (Windows or Mac), or Windows clients on the Wi-Fi. It's just the combination of Mac and Wi-Fi that leads to this. I've experimented with different SSIDs, passwords, different encryption, NO encryption, 5Ghz, 2.5Ghz, and on and on. No obvious connections.
It's not easily reproducible, and seems to consistently follow one or a few users around before going away and then affecting a different user or group of users for a while.