Do Zigbee2Mqtt devices....forgot what they're doing?

I’ve been storing a Xiaomi door/window sensor in a separate location from the Zigbee2MQTT dongle for a few weeks. Today I went to put it back and use it, and it wasn’t recognised/detected by the integration. I wondered if there is a timeout on the server for devices ‘dropping off the map’ and/or if the device itself goes into a sleep mode if not used for x amount of time?

Xiaomi are notorious devices that don’t follow the zigbee protocol to the same specifications as everyone else. So they tend to drop off more than other sensors. (You get what you pay for for cheap chinese sensors)

Anyway, I don’t have any of those devices but I’ve read that specific outlets and/or repeaters work great at stabilizing the Xiaomi devices on the zigbee mesh. IKEAs repeater and outlets are made by the same manufacturer as Xiaomi (I thought?). But the point is IKEAs device play nice with Xiaomi and can help with drop off.