@Gen3 that sounds very odd as when you applied the change to the hub it would have restarted in the process disconnected all of the WiFi devices which would have needed to be re-connected using the new password or using the WPS system which requires physical access to the hub to start the process. The only devices which would reconnect automatically are those connected by ethernet.
Do you have third party wiifi boosters? Are you by an chance misidentifying a device you havecreconnected yourself as the details on the hub's device list can be misleading including device being listed as unknown which only means tge device is not returning an identity not thst it isnt ine of your own devices.
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65inch Sky Glass, 3 Sky Streaming Pucks, Sky Ultrafast + and Sky SR213(white Wifi Max hub) main Wifi from 3 TP-Link Deco M4 units in access point mode
