My wireless network at home consists of:
2011UiAS running 6.45.7 (and consistently running the latest stable bits)
3 x RBcAPGi-5acD2nD also running 6.45.7, configured using CAPSman, with upgrade firmware served from the router. Local switching is enabled.
There are three SSIDs on each of 2.4GHz and 5GHz, two using WPA2-PSK and one using WPA2-Enterprise, with Radius provided by Jumpcloud.
One of the APs is linked to the 2011 by a PoE switch (router->switch->AP) and the other two are linked by powerline ethernet (router->switch->powerline->switch->AP).
Problem 1: when the router is updated, I pre-load the AP npk onto the router. The router upgrades and reboots, and the APs then upgrade and reboot. Following this, almost all the devices in the house are OK (iPad, iPhone, Macs, Amazon Echo, Firestick, Chromecast, Ring, etc). However, a Windows 7 laptop fails to connect to the PSK networks (it can't use the Enterprise network because we do not have administrative access to trust the radius certificate) until the router is rebooted again.
Problem 2: any disruption to the CAPs (last night, the power-cycling of the switch into which one of the APs and the Powerline to the other APs are plugged) causes the WPA2-Enterprise network to stop working, again until the router is rebooted.
The two problems may or may not be related, but both take the form "disruption to AP-router communications, communications restored, router requires reboot in order for some but not all wireless devices to be able to use the APs".