Make sure you’re joining the Xiaomi sensors close to the hub and leaving them there until they start reporting battery. Once it starts joining reporting battery you should be able to move it to where you want it. If you still have issues I suggest bringing it up in one of the Xiaomi threads like [OBSOLETE] Xiaomi Sensors and Button (beta) since it’s likely not related to the firmware release or hub disconnect issues.
I think by Zigbee motion you’re talking about a SmartSense Motion Sensor. Sounds like you’ve repaired that a few times and it’s still not working so I’d definitely suggest contacting support.