The Aqara devices is known to drop off Zigbee mesh when it route through a router/repeater that is not compatible. The repeater itself could be a well behaving repeater. It is just the Aqara device is handling the Zigbee protocol incorrectly. There could be other issues. However, this is probably the most common issue with Xiaomi Aqara devices.
There was a very long discussion about it in the DTH thread. Unfortunately, the thread is long. Within the thread, there are sub discussion about this if you are interested. Here is a link that may get you to the information about the drop off.