Fritz!OS 7.57 has an annoying bug which breaks device tracking, specifically in combination with 3rd party Access Points.
The issue is that when a device that is being tracked (like an iphone) connects to the wifi of the Fritz!Box itself, it gets registered a wireless connected device. When the tracked device roams to another (3rd party) Access Point, in older Fritz!OS’s it would get registered as LAN connected. With the new Fritz!OS 7.57 it no longer gets registered as LAN connected but as Idle. Even though you are still connected through the WiFi with the tracked device and everything works on the tracked device, Fritz!Box still says the tracked device is idle.
This issue is also in reverse. When you connect the tracked device first to the 3rd party Access Point it gets registered in the Fritz!Box as LAN connected. When you then roam to the wifi of the Fritz!Box it now becomes idle. In older OS’s it would simply switch to wireless connected.
Work around 1: My 3rd party Access Points are Devolo Magic 2 WiFi. With the Devolo Home Network integration you can do the device tracking with them too. So the tracked devices would remain “home” if they were roaming. However sometimes this would not work smoothly as the tracked device was not updated quick enough and the person would still be shown as “not home”.
Work around 2: don’t use the wifi of the Fritz!Box. So I basically switched off the wifi of the Fritz!Box and bought an extra Access Point (unifi U6-Pro). So all devices now exclusively connect through 3rd party Access Points. This causes (after a restart of the Fritz!Box and some time waiting) all wireless devices to be registered as LAN connected. When you then roam from one 3rd party Access Point to the other it remains LAN connected and doesn’t show as idle.
I first noticed this issue when my Fritz!Box 7490 was temporarily replaced with a newer model for testing purposes. This new model had the new OS installed and right away my device tracking stopped working when roaming through the house. My 7490 did not have the new OS so when I switched back to the 7490 Fritz!Box, the device tracking worked normal again. However a few weeks ago the 7490 was upgraded automatically to OS 7.57 and now behaves the same as the new model Fritz!Boxes.
I am in contact with AVM - the makers of the Fritz!Box, but the issue is very difficult to explain and return e-mails seem to suggest that they themselves do not understand the issue. If more people will complain about the issue, it might get resolved. Till then not using the Fritz!Box wifi has solved the issue.