I have the same behaviour with 2.29.1 (running in Docker) and had it before with the release from summer 2024. The lumi.sensor_magnet.aq2 worked well before.
Phoscon shows me for one of them for example that it was updated 46 days ago. The window is opened and closed every day. Repairing (without deleting) doesn’t change anything.
I have the same problem again (after Sonoff sensors (eWeLink) disconnected and not sending out updates) more and more with “eweLink TH1” (Sonoff SNZB-02). Looking on the network graph, I see links (green, yellow) between the missing (battery powered) devices and other active devices (as plugs or the raspbee gateway itself). As some of the newly disappeared devices disappeared only some weeks after first installation, I am sure that it is not the battery (which was shown to have 92% remaining capacity at the last update).
Any thoughts how to find the problem?