If you are using the Hubitat button controller app, you need to make sure you have defined all 6 buttons. I am no longer using mine directly connected to the Hubitat hub, but if I recall correctly, the driver showed that 6 buttons were available. Make sure your ms shows this.
For reliable connection, I would recommend you use the Xiaomi button driver from @markus and ensure your Zigbee mesh has only Xiaomi compatible mains powered repeaters. No Zigbee lights in the mesh with Xiaomi devices, except for Sengled (which will not interfere because they don’t try to repeat Zigbee signals).
