In the list "Known Wireless Devices in the Wi-Fi Network" under "Wi-Fi > Wi-Fi Network" ("Wireless > Radio Network"), the FRITZ!Box only displays wireless devices as connected if they are directly connected to the FRITZ!Box. Wireless devices that are connected to a Mesh Repeater (for example FRITZ!Repeater) are not displayed in this list or displayed as not connected.

You can find an overview of all of the devices that are connected to the FRITZ!Box or a Mesh Repeater under "Home Network > Mesh" in the FRITZ!Box Mesh Overview.