Zigbee2mqtt strange device disconnect

I have ~90 Zigbee devices in my network, most of them are routers. I run Z2M via a LilyZig coordinator fine.

Some of my devices are shown as offline from time to time, while the map show that they have good connection:


It is strange that the device still responds to group commands (on/off, dim) but I can’t access them on their own.

Any hints/thoughts on this?