Obviously this is a bug - for security reasons I would prefer it to be invisible and I can't think why making it invisible would cause intermittent wifi restarts but from testing this seems to be the case. Also note there are no competing 5Ghz wifi access points in my neighbourhood - clear spectrum, so its not interference.
Hidden SSID cause more problems then it helps. It is not really a security feature at all. See
here and
here on why.
"...the wireless driver must send the probe packet to the AP for the hidden SSID. We have seen that power settings defined on the NIC driver can influence whether the AP receives this probe."
Also, just because you can't see other 5Ghz network, doesn't mean they aren't there. They too might be hiding their SSID, which makes channel management near impossible. Hidden SSID died out when security got better with AES, and kind of like MAC filtering, just lead to a false sense of security which can cause you problems, as well as problems for others around you.