I get this periodically, usually after a period of non-use (tends to be a day or two, often with a device still connected.)
If I restart the daemon then everything is fine.
Not sure if it's triggered by the client system rebooting while a device is connected ... I haven't managed to pin it down that specifically.
Server version is: 4.2.0 (arm on a pi4)
Client is 5.0.8 (on Win10)
BTW ... is "check for updates" supposed to work? It never does for me!